Commit Graph

38 Commits

Author SHA1 Message Date
Lyude
f808f63372 drm/dp_helper: Perform throw-away read before actual read in drm_dp_dpcd_read()
This is part of a patch series to migrate all of the workarounds for
commonly seen behavior from bad sinks in intel_dp_dpcd_read_wake() to drm's
DP helper.

Some sinks will just return garbage for the first aux tranaction they
receive when coming out of sleep mode, so we need to perform an additional
read before the actual read to workaround this.

			    Changes since v5
- If the throwaway read in drm_dp_dpcd_read() fails, return the error
  from that instead of continuing. This follows the same logic we do in
  drm_dp_dpcd_access() (e.g. the error from the first transaction may
  differ from the errors that proceeding attempts might return).

Signed-off-by: Lyude <cpaul@redhat.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1460730335-5012-1-git-send-email-cpaul@redhat.com
2016-04-22 18:52:24 +02:00
Lyude
82922da391 drm/dp_helper: Retry aux transactions on all errors
This is part of a patch series to migrate all of the workarounds for
commonly seen behavior from bad sinks in intel_dp_dpcd_read_wake() to
drm's DP helper.

We cannot rely on sinks NACKing or deferring when they can't receive
transactions, nor can we rely on any other sort of consistent error to
know when we should stop retrying. As such, we need to just retry
unconditionally on errors. We also make sure here to return the error we
encountered during the first transaction, since it's possible that
retrying the transaction might return a different error then we had
originally.

This, along with the previous patch, work around a weird bug with the
ThinkPad T560's and it's dock. When resuming the laptop, it appears that
there's a short period of time where we're unable to complete any aux
transactions, as they all immediately timeout. The only machine I'm able
to reproduce this on is the T560 as other production Skylake models seem
to be fine. The period during which AUX transactions fail appears to be
around 22ms long. AFAIK, the dock for the T560 never actually turns off,
the only difference is that it's in SST mode at the start of the resume
process, so it's unclear as to why it would need so much time to come
back up.

There's been a discussion on this issue going on for a while on the
intel-gfx mailing list about this that has, in addition to including
developers from Intel, also had the correspondence of one of the
hardware engineers for Intel:

http://www.spinics.net/lists/intel-gfx/msg88831.html
http://www.spinics.net/lists/intel-gfx/msg88410.html

We've already looked into a couple of possible explanations for the
problem:

- Calling intel_dp_mst_resume() before right fix.
  intel_runtime_pm_enable_interrupts(). This was the first fix I tried,
  and while it worked it definitely wasn't the right fix. This worked
  because DP aux transactions don't actually require interrupts to work:

	static uint32_t
	intel_dp_aux_wait_done(struct intel_dp *intel_dp, bool has_aux_irq)
	{
		struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
		struct drm_device *dev = intel_dig_port->base.base.dev;
		struct drm_i915_private *dev_priv = dev->dev_private;
		i915_reg_t ch_ctl = intel_dp->aux_ch_ctl_reg;
		uint32_t status;
		bool done;

	#define C (((status = I915_READ_NOTRACE(ch_ctl)) & DP_AUX_CH_CTL_SEND_BUSY) == 0)
		if (has_aux_irq)
			done = wait_event_timeout(dev_priv->gmbus_wait_queue, C,
						  msecs_to_jiffies_timeout(10));
		else
			done = wait_for_atomic(C, 10) == 0;
		if (!done)
			DRM_ERROR("dp aux hw did not signal timeout (has irq: %i)!\n",
				  has_aux_irq);
	#undef C

		return status;
	}

  When there's no interrupts enabled, we end up timing out on the
  wait_event_timeout() call, which causes us to check the DP status
  register once to see if the transaction was successful or not. Since
  this adds a 10ms delay to each aux transaction, it ends up adding a
  long enough delay to the resume process for aux transactions to become
  functional again. This gave us the illusion that enabling interrupts
  had something to do with making things work again, and put me on the
  wrong track for a while.

- Interrupts occurring when we try to perform the aux transactions
  required to put the dock back into MST mode. This isn't the problem,
  as the only interrupts I've observed that come during this timeout
  period are from the snd_hda_intel driver, and disabling that driver
  doesn't appear to change the behavior at all.

- Skylake's PSR block causing issues by performing aux transactions
  while we try to bring the dock out of MST mode. Disabling PSR through
  i915's command line options doesn't seem to change the behavior
  either, nor does preventing the DMC firmware from being loaded.

Since this investigation went on for about 2 weeks, we decided it would
be better for the time being to just workaround this issue by making
sure AUX transactions wait a short period of time before retrying.

Signed-off-by: Lyude <cpaul@redhat.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1460559513-32280-3-git-send-email-cpaul@redhat.com
2016-04-22 18:51:54 +02:00
Lyude
e1083ff351 drm/dp_helper: Always wait before retrying native aux transactions
This is part of a patch series to migrate all of the workarounds for
commonly seen behavior from bad sinks in intel_dp_dpcd_read_wake() to
drm's DP helper.

Some sinks need some time during the process of resuming the system from
sleep before they're ready to handle transactions. While it would be
nice if they responded with NACKs in these scenarios, this isn't always
the case as a few sinks will just timeout on all of the transactions
they receive until they're ready.

Signed-off-by: Lyude <cpaul@redhat.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1460559513-32280-2-git-send-email-cpaul@redhat.com
2016-04-22 18:51:24 +02:00
Rob Clark
7779c5e23c drm/dp: move hw_mutex up the call stack
1) don't let other threads trying to bang on aux channel interrupt the
defer timeout/logic
2) don't let other threads interrupt the i2c over aux logic

Technically, according to people who actually have the DP spec, this
should not be required.  In practice, it makes some troublesome Dell
monitor (and perhaps others) work, so probably a case of "It's compliant
if it works with windows" on the hw vendor's part..

v2: rebased to come before DPCD/AUX logging patch for easier backport
to stable branches.

Reported-by: Dave Wysochanski <dwysocha@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1274157
Cc: stable@vger.kernel.org
Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2016-04-01 13:17:36 +10:00
Rafael Antognolli
e94cb37b34 drm/dp: Add a drm_aux-dev module for reading/writing dpcd registers.
This module is heavily based on i2c-dev. Once loaded, it provides one
dev node per DP AUX channel, named drm_dp_auxN, where N is an integer.

It's possible to know which connector owns this aux channel by looking
at the respective sysfs /sys/class/drm_aux_dev/drm_dp_auxN/connector, if
the connector device pointer was correctly set in the aux helper struct.

Two main operations are provided on the registers read and write. The
address of the register to be read or written is given using lseek. The
seek position is updated upon read or write.

v2:
 - lseek is used to select the register to read/write
 - read/write are used instead of ioctl
 - no blocking_notifier is used, just a direct callback

v3:
 - use drm_dp_aux_dev prefix for public functions
 - chardev is named drm_dp_auxN
 - read/write don't allocate a buffer anymore, and transfer up to 16 bytes a
   time
 - remove notifier list from the implementation
 - option on menuconfig is now a boolean
 - add inline stub functions to avoid breakage when this option is disabled

v4:
 - fix build system changes - actually disable this module when not selected.

v5:
 - Use kref to avoid device closing while still in use
 - Don't use list, use an idr for storing aux_dev
 - Remove "connector" attribute
 - set aux.dev to the connector drm_connector device, instead of
   drm_device

v6:
 - Use atomic_t for usage count
 - Use a mutex instead of spinlock for idr lock
 - Destroy chardev immediately on unregister
 - other minor suggestions from Ville

v7:
 - style fixes
 - error handling fixes

v8:
 - more error handling fixes

v9:
 - remove module_init and module_exit, and add drm_dp_aux_dev_init/exit
 to drm_kms_helper_init/exit.

Signed-off-by: Rafael Antognolli <rafael.antognolli@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1453417821-2811-3-git-send-email-rafael.antognolli@intel.com
2016-02-12 14:22:40 +01:00
Daniel Vetter
646db260b8 Linux 4.3-rc2
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Merge tag 'v4.3-rc2' into topic/drm-misc

Backmerge Linux 4.3-rc2 because of conflicts in the dp helper code
between bugfixes and new code. Just adjacent lines really.

On top of that there's a silent conflict in the new fsl-dcu driver
merged into 4.3 and

commit 844f9111f6
Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date:   Wed Sep 2 10:42:40 2015 +0200

    drm/atomic: Make prepare_fb/cleanup_fb only take state, v3.

which Thierry Reding spotted and provided a fixup for.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-09-24 17:18:41 +02:00
Ville Syrjälä
68ec2a2a24 drm/dp: Use I2C_WRITE_STATUS_UPDATE to drain partial I2C_WRITE requests
When an i2c WRITE gets an i2c defer or short i2c ack reply, we are
supposed to switch the request from I2C_WRITE to I2C_WRITE_STATUS_UPDATE
when we continue to poll for the completion of the request.

v2: Don't assume DP_AUX_I2C_WRITE is 0 even though it is, to make the
    code more obvious to the casual reader (Jani)

Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Resolve conflict due to changed context.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-09-08 20:22:57 +02:00
Ville Syrjälä
f36203be60 drm/dp: Add dp_aux_i2c_speed_khz module param to set the assume i2c bus speed
To help with debugging i2c-over-aux issues, add a module parameter than
can be used to tweak the assumed i2c bus speed, and thus the maximum
number of retries we will do for each aux message.

Cc: Simon Farnsworth <simon.farnsworth@onelan.com>
Cc: moosotc@gmail.com
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Simon Farnsworth <simon.farnsworth@onelan.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2015-09-02 16:13:43 +03:00
Ville Syrjälä
4efa83c8c7 drm/dp: Adjust i2c-over-aux retry count based on message size and i2c bus speed
Calculate the number of retries we should do for each i2c-over-aux
message based on the time it takes to perform the i2c transfer vs. the
aux transfer. We assume the shortest possible length for the aux
transfer, and the longest possible (exluding clock stretching) for the
i2c transfer.

The DP spec has some examples on how to calculate this, but we don't
calculate things quite the same way. The spec doesn't account for the
retry interval (assumes immediate retry on defer), and doesn't assume
the best/worst case behaviour as we do.

Note that currently we assume 10 kHz speed for the i2c bus. Some real
world devices (eg. some Apple DP->VGA dongle) fails with less than 16
retries. and that would correspond to something close to 15 kHz (with
our method of calculating things) But let's just go for 10 kHz to be
on the safe side. Ideally we should query/set the i2c bus speed via
DPCD but for now this should at leaast remove the regression from the
1->16 byte trasnfer size change. And of course if the sink completes
the transfer quicker this shouldn't slow things down since we don't
change the interval between retries.

I did a few experiments with a DP->DVI dongle I have that allows you
to change the i2c bus speed. Here are the results of me changing the
actual bus speed and the assumed bus speed and seeing when we start
to fail the operation:

actual i2c khz          assumed i2c khz         max retries
1                       1 ok -> 2 fail          211 ok -> 106 fail
5                       8 ok -> 9 fail          27 ok -> 24 fail
10                      17 ok -> 18 fail        13 ok -> 12 fail
100                     210 ok -> 211 fail      2 ok -> 1 fail

So based on that we have a fairly decent safety margin baked into
the formula to calculate the max number of retries.

Fixes a regression with some DP dongles from:
commit 1d002fa720
Author: Simon Farnsworth <simon.farnsworth@onelan.co.uk>
Date:   Tue Feb 10 18:38:08 2015 +0000

    drm/dp: Use large transactions for I2C over AUX

v2: Use best case for AUX and worst case for i2c (Simon Farnsworth)
    Add a define our AUX retry interval and account for it
v3: Make everything usecs to avoid confusion about units (Daniel)
    Add a comment reminding people about the AUX bitrate (Daniel)
    Use DIV_ROUND_UP() since we're after the "worst" case for i2c

Cc: Simon Farnsworth <simon.farnsworth@onelan.com>
Cc: moosotc@gmail.com
Tested-by: moosotc@gmail.com
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91451
Reviewed-by: Simon Farnsworth <simon.farnsworth@onelan.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2015-09-02 16:08:20 +03:00
Ville Syrjälä
79a2b161c1 drm/dp: Define AUX_RETRY_INTERVAL as 500 us
Currently we react to native and i2c defers by waiting either 400-500 us
or 500-600 us, depending on which code path we take. Consolidate them
all to one define AUX_RETRY_INTERVAL which defines the minimum interval.
Since we've been using two different intervals pick the longer of them
and define AUX_RETRY_INTERVAL as 500 us. For the maximum just use
AUX_RETRY_INTERVAL+100 us.

I want to have a define for this so that I can use it when calculating
the estimated duration of i2c-over-aux transfers. Without a define it
would be very easy to change the sleep duration and neglect to update
the i2c-over-aux estimates.

Cc: Simon Farnsworth <simon.farnsworth@onelan.com>
Cc: moosotc@gmail.com
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Simon Farnsworth <simon.farnsworth@onelan.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2015-09-02 15:49:20 +03:00
Todd Previte
396aa4451e drm: Fix for DP CTS test 4.2.2.5 - I2C DEFER handling
For test 4.2.2.5 to pass per the Link CTS Core 1.2 rev1.1 spec, the source
device must attempt at least 7 times to read the EDID when it receives an
I2C defer. The normal DRM code makes only 7 retries, regardless of whether
or not the response is a native defer or an I2C defer. Test 4.2.2.5 fails
since there are native defers interspersed with the I2C defers which
results in less than 7 EDID read attempts.

The solution is to add the numer of defers to the retry counter when an I2C
DEFER is returned such that another read attempt will be made. This situation
should normally only occur in compliance testing, however, as a worse case
real-world scenario, it would result in 13 attempts ( 6 native defers, 7 I2C
defers) for a single transaction to complete. The net result is a slightly
slower response to an EDID read that shouldn't significantly impact overall
performance.

V2:
- Added a check on the number of I2C Defers to limit the number
  of times that the retries variable will be decremented. This
  is to address review feedback regarding possible infinite loops
  from misbehaving sink devices.
V3:
- Fixed the limit value to 7 instead of 8 to get the correct retry
  count.
- Combined the increment of the defer count into the if-statement
V4:
- Removed i915 tag from subject as the patch is not i915-specific
V5:
- Updated the for-loop to add the number of i2c defers to the retry
  counter such that the correct number of retry attempts will be
  made

Signed-off-by: Todd Previte <tprevite@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-04-20 09:29:41 -07:00
Todd Previte
747552b947 drm: Fix the 'native defer' message in drm_dp_i2c_do_msg()
The debug message is missing a newline at the end and it makes the
logs hard to read when a device defers a lot. Simple 2-character fix
adds the newline at the end.

Signed-off-by: Todd Previte <tprevite@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-04-16 14:42:04 +02:00
Ville Syrjälä
fb8c5e4988 drm/dp: Print the number of bytes processed for aux nacks
When doing a native or i2c aux write the sink will indicate the number
of bytes written even if it the nacks the transfer. When we receive a
nack we just return an error upwards, but it might still be interesting
to see how many bytes made it before the nack. So include that information
in the debug messages.

v2: Also print the message size (Jani)

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-03-23 16:22:29 +01:00
Simon Farnsworth
1d002fa720 drm/dp: Use large transactions for I2C over AUX
Older DisplayPort to DVI-D Dual Link adapters designed by Bizlink have bugs
in their I2C over AUX implementation (fixed in newer revisions). They work
fine with Windows, but fail with Linux.

It turns out that they cannot keep an I2C transaction open unless the
previous read was 16 bytes; shorter reads can only be followed by a zero
byte transfer ending the I2C transaction.

Copy Windows's behaviour, and read 16 bytes at a time. If we get a short
reply, assume that there's a hardware bottleneck, and shrink our read size
to match. For this purpose, use the algorithm in the DisplayPort 1.2 spec,
in the hopes that it'll be closest to what Windows does.

Also provide an unsafe module parameter for testing smaller transfer sizes,
in case there are sinks out there that cannot work with Windows.

Note also that despite the previous comment in drm_dp_i2c_xfer, this speeds
up native DP EDID reads; Ville Syrjälä <ville.syrjala@linux.intel.com> found
the following changes in his testing:

Device under test:     old  -> with this patch
DP->DVI (OUI 001cf8):  40ms -> 35ms
DP->VGA (OUI 0022b9):  45ms -> 38ms
Zotac DP->2xHDMI:      25ms ->  4ms
Asus PB278 monitor:    22ms ->  3ms

A back of the envelope calculation shows that peak theoretical transfer rate
for 1 byte reads is around 60 kbit/s; with 16 byte reads, this increases to
around 500 kbit/s, which explains the increase in speed.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=55228
Tested-by: Aidan Marks <aidanamarks@gmail.com> (v3)
Signed-off-by: Simon Farnsworth <simon.farnsworth@onelan.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-03-11 22:04:56 +01:00
Rob Clark
d816f07736 drm/dp: add drm_dp_link_power_down() helper
We had _power_up(), but drivers also need to be able to power down.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
2015-02-01 15:06:42 -05:00
Dave Airlie
19a93f042f drm/dp: retry AUX transactions 32 times (v1.1)
At least on two MST devices I've tested with, when
they are link training downstream, they are totally
unable to handle aux ch msgs, so they defer like nuts.
I tried 16, it wasn't enough, 32 seems better.

This fixes one Dell 4k monitor and one of the
MST hubs.

v1.1: fixup comment (Tom).

Acked-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-12-09 09:56:44 +10:00
Todd Previte
e9cf6194ab drm/dp: Add counters in the drm_dp_aux struct for I2C NACKs and DEFERs
These counters are used for Displayort compliance testing to detect error
conditions when executing tests 4.2.2.4 and 4.2.2.5 in the Displayport Link
CTS specificaiton. They determine whether to use the preferred/requested
mode or the failsafe mode during these tests.

V2:
- Addressed previous review feedback
- Updated commit message
- Changed from uint8_t to uint32_t

Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Todd Previte <tprevite@gmail.com>
[danvet: s/uint32_t/unsigned/ for clearer intent. Also drop the i915
from the subject, it's all core stuff.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-11-05 14:03:22 +01:00
Daniel Vetter
e45708976a drm/dp-helper: Move the legacy helpers to gma500
Except for gma500 all drivers are converted to the new style helpers,
which have much better abstraction of the underlying hw protocols and
already much more helper functions (including the entire mst library)
on top of them. Since no one seems to work on converting gma500 let's
just move the code away so that new drivers don't end up accidentally
using this.

Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
[danvet: Add __deprecated as requested by Alan. Also add a short FIXME
comment and drop the EXPORT_SYMBOL which is no longer needed.]
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2014-10-23 09:24:06 +02:00
Dave Airlie
4f71d0cb76 drm/dp: add a hw mutex around the transfer functions. (v2)
This should avoid races between connector probing and HPD
irqs in the future, currently mode_config.mutex blocks this
possibility.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-06-05 09:54:29 +10:00
Daniel Vetter
2a8dc638f7 drm/dp-helper: Deprecate old i2c-over-dp_aux heleprs
Only gma500 is still using this, once that's converted we can kill all
this code. If that conversion doesn't happen soonish I think we should
just move this helper code into the gma500 driver itself to avoid
abuse from new drivers.

Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-06-02 09:57:28 +02:00
Thierry Reding
171f975d4c drm/dp: Fix typo in comment
Replace an occurrence of "adapater" with "adapter".

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-04-29 12:33:46 +02:00
Alex Deucher
732d50b431 drm/dp/i2c: Update comments about common i2c over dp assumptions (v3)
If you are using the common dp over i2c functionality, it is
asumed that the aux transfer function does not modify the any
of the msg structure other than the reply field.  Doing so
breaks the logic in the common code.

v2: update struct drm_dp_aux comments about assumptions
v3 (chk): rebased on upstream changes

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Thierry Reding <treding@nvidia.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
2014-04-08 16:12:39 +02:00
Alex Deucher
ccdb516e18 drm/dp/i2c: send bare addresses to properly reset i2c connections (v4)
We need bare address packets at the start and end of
each i2c over aux transaction to properly reset the connection
between transactions.  This mirrors what the existing dp i2c
over aux algo currently does.

This fixes EDID fetches on certain monitors especially with
dp bridges.

v2: update as per Ville's comments
    - Set buffer to NULL for zero sized packets
    - abort the entre transaction if one of the messages fails
v3: drop leftover debugging code
v4: integrate Thierry's comments
    - add comments about address only transactions
    - switch back to i and j

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Thierry Reding <treding@nvidia.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
2014-04-08 16:12:38 +02:00
Dave Airlie
aa17edff0a drm/dp_helper: don't return EPROTO for defers (v2)
If we get a msg.reply of REPLY_DEFER, we also get an err of 0
so we fail reads with 0 < size and return -EPROTO instead of trying
again.

v2: same fix in i2c code.

Found writing MST support.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2014-04-05 16:06:34 +10:00
Dave Airlie
66e514c14a Merge tag 'drm-intel-next-2014-03-21' of git://anongit.freedesktop.org/drm-intel into drm-next
- Inherit/reuse firmwar framebuffers (for real this time) from Jesse, less
  flicker for fastbooting.
- More flexible cloning for hdmi (Ville).
- Some PPGTT fixes from Ben.
- Ring init fixes from Naresh Kumar.
- set_cache_level regression fixes for the vma conversion from Ville&Chris.
- Conversion to the new dp aux helpers (Jani).
- Unification of runtime pm with pc8 support from Paulo, prep work for runtime
  pm on other platforms than HSW.
- Larger cursor sizes (Sagar Kamble).
- Piles of improvements and fixes all over, as usual.

* tag 'drm-intel-next-2014-03-21' of git://anongit.freedesktop.org/drm-intel: (75 commits)
  drm/i915: Include a note about the dangers of I915_READ64/I915_WRITE64
  drm/i915/sdvo: fix questionable return value check
  drm/i915: Fix unsafe loop iteration over vma whilst unbinding them
  drm/i915: Enabling 128x128 and 256x256 ARGB Cursor Support
  drm/i915: Print how many objects are shared in per-process stats
  drm/i915: Per-process stats work better when evaluated per-process
  drm/i915: remove rps local variables
  drm/i915: Remove extraneous MMIO for RPS
  drm/i915: Rename and comment all the RPS *stuff*
  drm/i915: Store the HW min frequency as min_freq
  drm/i915: Fix coding style for RPS
  drm/i915: Reorganize the overclock code
  drm/i915: init pm.suspended earlier
  drm/i915: update the PC8 and runtime PM documentation
  drm/i915: rename __hsw_do_{en, dis}able_pc8
  drm/i915: kill struct i915_package_c8
  drm/i915: move pc8.irqs_disabled to pm.irqs_disabled
  drm/i915: remove dev_priv->pc8.enabled
  drm/i915: don't get/put PC8 when getting/putting power wells
  drm/i915: make intel_aux_display_runtime_get get runtime PM, not PC8
  ...

Conflicts:
	drivers/gpu/drm/i915/intel_display.c
	drivers/gpu/drm/i915/intel_dp.c
2014-04-03 07:51:54 +10:00
Alex Deucher
743b1e32f2 drm/dp: make aux retries less chatty
Switch to debug only to avoid flooding the logs.
This mirrors the behavior in some other drivers.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Christian König <christian.koenig@amd.com>
2014-03-25 13:13:20 +01:00
Jani Nikula
9dc4056026 drm/dp: let drivers specify the name of the I2C-over-AUX adapter
Let the drivers specify the name of the I2C-over-AUX adapter to maintain
backwards compatibility in the sysfs when converting to the new
I2C-over-AUX helper infrastructure.

The i915 driver currently uses DPDDC-A to DPDDC-D as names for the DP
i2c adapters. These names show up in the i2c sysfs name attribute. We'd
like to be able to maintain that when switching over to the new helpers.

Due to i2c device and connector cleanup ordering issues we also recently
made the drm device (instead of connector) the parent of the i2c
adapters:

commit 80f65de3c9
Author: Imre Deak <imre.deak@intel.com>
Date:   Tue Feb 11 17:12:49 2014 +0200

    drm/i915: dp: fix order of dp aux i2c device cleanup

With the name picked up from the adapter parent using dev_name(), it
would be the same for all i2c adapters with the current I2C-over-AUX
helpers.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2014-03-18 10:53:14 +01:00
Thierry Reding
88759686c7 drm/dp: Allow registering AUX channels as I2C busses
Implements an I2C-over-AUX I2C adapter on top of the generic drm_dp_aux
infrastructure. It extracts the retry logic from existing drivers, which
should help in porting those drivers to this new helper.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
Changes in v5:
- move comments partially to to header file
- keep MOT set between I2C messages
- return -EPROTO on short reads

Changes in v4:
- fix typo "bitrate" -> "bit rate"

Changes in v3:
- add back DRM_DEBUG_KMS and DRM_ERROR messages
- embed i2c_adapter within struct drm_dp_aux
- fix typo in comment
2014-02-26 17:21:34 +01:00
Thierry Reding
516c0f7c0a drm/dp: Add DisplayPort link helpers
Add a helper to probe a DP link (read out the supported DPCD revision,
maximum rate, link count and capabilities) as well as power up the DP
link and configure it accordingly.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
Changes in v5:
- export helpers

Changes in v4:
- fix a couple of typos in comments as pointed out by Alex Deucher

Changes in v3:
- split into drm_dp_link_power_up() and drm_dp_link_configure()
- do not change sink state for DPCD versions earlier than 1.1
- sleep for 1-2 ms after setting local sink to D0 state
- read and write consecutive registers where possible
- read DPCD revision when link is probed
- remove duplicate kerneldoc
2014-02-26 17:21:34 +01:00
Thierry Reding
8d4adc6a58 drm/dp: Add drm_dp_dpcd_read_link_status()
The function reads the link status (6 bytes starting at offset 0x202)
from the DPCD so that it can be conveniently passed to other DPCD
helpers.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
2014-02-26 17:21:33 +01:00
Thierry Reding
c197db75ff drm/dp: Add AUX channel infrastructure
This is a superset of the current i2c_dp_aux bus functionality and can
be used to transfer native AUX in addition to I2C-over-AUX messages.

Helpers are provided to read and write the DPCD, either blockwise or
byte-wise. Many of the existing helpers for DisplayPort take a copy of a
portion of the DPCD and operate on that, without a way to write data
back to the DPCD (e.g. for configuration of the link).

Subsequent patches will build upon this infrastructure to provide common
functionality in a generic way.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
Changes in v5:
- move comments partially to struct drm_dp_aux_msg in header file
- return -EPROTO on short reads in DPCD helpers

Changes in v4:
- fix a typo in a comment

Changes in v3:
- reorder drm_dp_dpcd_writeb() arguments to be more intuitive
- return number of bytes transferred in drm_dp_dpcd_write()
- factor out drm_dp_dpcd_access()
- describe error codes
2014-02-26 17:21:32 +01:00
Jani Nikula
0aec288130 drm/dp: constify DP DPCD helpers
None of the DP DPCD helpers need to modify the DPCD.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-10-01 15:28:57 +10:00
Daniel Vetter
28164fdad8 drm/doc: add new dp helpers into drm DocBook
I didn't bother with documenting the really trivial new "extract
something from dpcd" helpers, but the i2c over aux ch is now
documented a bit.

v2: Clarify the comment for i2c_dp_aux_add_bus a bit.

v3: Fix more spelling fail spotted by Laurent Pinchart.

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2012-11-28 20:26:53 +10:00
Daniel Vetter
3b5c662e8f drm: extract dp link bw helpers
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-10-22 22:34:47 +02:00
Daniel Vetter
1a644cd47c drm: extract dp link train delay functions from radeon
This requires a few changes since that dpcd value is above the
range currently cached by radeon. I've check the dp specs, and
above 0xf there's a big gap and nothing that looks like we should
cache it while a given device is plugged in. It's also the same value
that i915.ko uses.

Hence extend the various dpcd arrays in the radeon driver, use
proper symbolic constants where applicable (one place overallocated
the dpcd array to 25 bytes). Then also drop the rd_interval cache -
radeon_dp_link_train_init re-reads the dpcd block, so the values we'll
consume in train_cr and train_ce will always be fresh.

To avoid needless diff-churn, #define the old size of dpcd as the new
one and keep it around.

v2: Alex Deucher noticed one place where I've forgotten to replace 8
with DP_RECEIVER_CAP_SIZE.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-10-22 22:34:46 +02:00
Daniel Vetter
0f037bdee1 drm: extract helpers to compute new training values from sink request
Safe for the minor difference that the intel versions get an offset
into the link_status as an argument, both are the same again.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-10-22 22:34:45 +02:00
Daniel Vetter
1ffdff134e drm: dp helper: extract drm_dp_channel_eq_ok
radeon and intel use the exact same definition.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-10-22 22:23:36 +02:00
Daniel Vetter
00ae9a456d drm: rename drm_dp_i2c_helper.c to drm_dp_helper.c
I want to move some dp link training helpers into this place, so in
the future this won't be just about i2c any longer.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-10-22 22:20:31 +02:00