Commit Graph

186 Commits

Author SHA1 Message Date
Keith Packard
9a10f401a4 drm/i915: Use DPCD value for max DP lanes.
The BIOS VBT value for an eDP panel has been shown to be incorrect on
one machine, and we haven't found any machines where the DPCD value
was wrong, so we'll use the DPCD value everywhere.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-11-16 20:26:27 -08:00
Keith Packard
b34f1f0931 drm/i915: Initiate DP link training only on the lanes we'll be using
Limit the link training setting command to the lanes needed for the
current mode. It seems vaguely possible that a monitor will try to
train the other lanes and fail in some way, so this seems like the
safer plan.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-11-16 20:26:27 -08:00
Keith Packard
f2e8b18af9 drm/i915: Remove trailing white space
Found a couple of bare tabs in intel_dp.c

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-11-16 20:26:26 -08:00
Keith Packard
cdb0e95bf5 drm/i915: Try harder during dp pattern 1 link training
Instead of going through the sequence just once, run through the whole
set up to 5 times to see if something can work. This isn't part of the
DP spec, but the BIOS seems to do it, and given that link training
failure is so bad, it seems reasonable to follow suit.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-11-16 20:26:26 -08:00
Keith Packard
21264c638b drm/i915: Make DP prepare/commit consistent with DP dpms
Make sure the sequence of operations in all three functions makes
sense:

 1) The backlight must be off unless the screen is running
 2) The link must be running to turn the eDP panel on/off
 3) The CPU eDP PLL must be running until everything is off

Signed-off-by: Keith Packard <keithp@keithp.com>
2011-11-16 20:26:26 -08:00
Keith Packard
99ea7127a3 drm/i915: Let panel power sequencing hardware do its job
The panel power sequencing hardware tracks the stages of panel power
sequencing and signals when the panel is completely on or off. Instead
of blindly assuming the panel timings will work, poll the panel power
status register until it shows the correct values.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-11-16 20:26:26 -08:00
Keith Packard
417e822dee drm/i915: Treat PCH eDP like DP in most places
PCH eDP has many of the same needs as regular PCH DP connections,
including the DP_CTl bit settings, the TRANS_DP_CTL register.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-11-16 20:26:26 -08:00
Keith Packard
93f62dad5f drm/i915: Remove link_status field from intel_dp structure
No persistent data was ever stored here, so link_status is instead
allocated on the stack as needed.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-11-16 20:26:25 -08:00
Keith Packard
832dd3c17f drm/i915: Move common PCH_PP_CONTROL setup to ironlake_get_pp_control
Every usage of PCH_PP_CONTROL sets the PANEL_UNLOCK_REGS value to
ensure that writes will be respected, move this to a common function
to make the driver cleaner.

No functional changes.

Signed-off-by: Keith Packard <keithp@keithp.com>
2011-11-16 20:26:25 -08:00
Keith Packard
627f7675f0 drm/i915: Use mode_config.mutex in ironlake_panel_vdd_work
Use of the struct_mutex is not correct for locking in mode setting paths.

Signed-off-by: Keith Packard <keithp@keithp.com>
2011-11-01 09:14:56 -07:00
Adam Jackson
82d165557e drm/i915/dp: Fix eDP on PCH DP on CPT/PPT
According to the gen6 docs, only the DP_A port (on-CPU eDP) still uses
the old IBX bit shift for the link training pattern setup bits.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-20 23:22:03 -07:00
Adam Jackson
1c95822afe drm/i915/dp: Introduce is_cpu_edp()
The obvious counterpart to is_pch_edp().  Convert existing instances of
the idiom to the new routine.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-20 23:22:03 -07:00
Jesse Barnes
a60f0e38d7 drm/i915: add DP test request handling
DPCD 1.1+ adds some automated test infrastructure support.  Add support
for reading the IRQ source and jumping to a test handling routine if
needed.  Subsequent patches will handle particular tests; this patch
just ACKs any requested tests by default.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-20 23:22:01 -07:00
Jesse Barnes
a2006cf5a7 drm/i915: read full receiver capability field during DP hot plug
Read link status first, followed by the full DPCD receiver cap field
rather than just the first 8 bytes.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-20 23:22:00 -07:00
Adam Jackson
dc22ee6fc1 drm/i915/dp: Remove eDP special cases from bandwidth checks
These were just working around the math being wrong.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-20 23:22:00 -07:00
Adam Jackson
cd9dde44f4 drm/i915/dp: Fix the math in intel_dp_link_required
The previous code was confused about units, which is pretty reasonable
given that the units themselves are confusing.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-20 23:21:59 -07:00
Jesse Barnes
d4270e57ef drm/i915: export a CPT mode set verification function
At the point where we check, we can't do much about the failure, but it
can aid debugging.  Note that the auto-train override bit will be reset
as part of normal mode setting with this patch if a pipe ever does get
stuck, but that's consistent with the workaround for CPT provided by the
hardware team.  This patch helped catch the fact that the pipe wasn't
running in the !composite sync FDI case on my IVB SDV, so has already
shown to be useful.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-By: Eugeni Dodonov <eugeni.dodonov@intel.com>
Reviewed-By: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-20 23:21:56 -07:00
Jesse Barnes
27f8227b1e drm/i915: support 3 pipes on IVB+
Well almost anyway.  IVB has 3 planes, pipes, transcoders, and FDI
interfaces, but only 2 pipe PLLs.  So two of the pipes must use the same
pipe timings (e.g. 2 DP plus one other, or two HDMI with the same mode
and one other, etc.).

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-By: Eugeni Dodonov <eugeni.dodonov@intel.com>
Reviewed-By: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-20 15:26:42 -07:00
Keith Packard
86a3073e48 Merge branch 'edp-training-fixes' into drm-intel-next
Conflicts:
	drivers/gpu/drm/i915/intel_dp.c

Just whitespace change conflicts
2011-10-20 14:10:07 -07:00
Keith Packard
32ce697c53 drm/i915: No need to wait for eDP power off delay if panel is on
If the panel is powered up, there's no need to delay for the 'off'
interval when turning the panel on.

Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-12 10:37:46 -06:00
Keith Packard
05ce1a4961 drm/i915: Restrict ILK-specific eDP power hack to ILK
This eliminates a fairly long delay when power sequencing newer
hardware

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2011-10-12 10:37:38 -06:00
Keith Packard
bd94315971 drm/i915: Disable eDP VDD in a delayed work proc instead of synchronously
There's no good reason to turn off the eDP force VDD bit synchronously
while probing devices; that just sticks a huge delay into all mode
setting paths. Instead, queue a delayed work proc to disable the VDD
force bit and then remember when that fires to ensure that the
appropriate delay is respected before trying to turn it back on.

Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-06 08:57:02 -07:00
Keith Packard
ebf33b1881 drm/i915: Create helper functions to determine eDP power state
We need to check eDP VDD force and panel on in several places, so
create some simple helper functions to avoid duplicating code.

Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-06 08:57:01 -07:00
Keith Packard
7d639f35b7 drm/i915: edp_panel_on does not need to return a bool
The return value was unused, so just stop doing that.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2011-10-06 08:57:01 -07:00
Keith Packard
d15456de79 drm/i915: Move eDP panel fixed mode from dev_priv to intel_dp
This value doesn't come directly from the VBT, and so is rather
specific to the particular DP output.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2011-10-06 08:57:00 -07:00
Keith Packard
f01eca2e52 drm/i915: Correct eDP panel power sequencing delay computations
Store the panel power sequencing delays in the dp private structure,
rather than the global device structure. Who knows, maybe we'll get
more than one eDP device in the future.

From the eDP spec, we need the following numbers:

 T1 + T3	Power on to Aux Channel operation (panel_power_up_delay)

		This marks how long it takes the panel to boot up and
		get ready to receive aux channel communications.

 T8		Video signal to backlight on (backlight_on_delay)

		Once a valid video signal is being sent to the device,
		it can take a while before the panel is actuall
		showing useful data. This delay allows the panel
		to get something reasonable up before the backlight
		is turned on.

 T9		Backlight off to video off (backlight_off_delay)

		Turning the backlight off can take a moment, so
		this delay makes sure there is still valid video
		data on the screen.

 T10		Video off to power off (panel_power_down_delay)

		Presumably this delay allows the panel to perform
		an orderly shutdown of the display.

 T11 + T12	Power off to power on (panel_power_cycle_delay)

		So, once you turn the panel off, you have to wait a
		while before you can turn it back on. This delay is
		usually the longest in the entire sequence.

Neither the VBIOS source code nor the hardware documentation has a
clear mapping between the delay values they provide and those required
by the eDP spec. The VBIOS code actually uses two different labels for
the delay values in the five words of the relevant VBT table.

**** MORE LATER ***

Look at both the current hardware register settings and the VBT
specified panel power sequencing timings. Use the maximum of the two
delays, to make sure things work reliably. If there is no VBT data,
then those values will be initialized to zero, so we'll just use the
values as programmed in the hardware. Note that the BIOS just fetches
delays from the VBT table to place in the hardware registers, so we
should get the same values from both places, except for rounding.

VBT doesn't provide any values for T1 or T2, so we'll always just use
the hardware value for that.

The panel power up delay is thus T1 + T2 + T3, which should be
sufficient in all cases.

The panel power down delay is T1 + T2 + T12, using T1+T2 as a proxy
for T11, which isn't available anywhere.

For the backlight delays, the eDP spec says T6 + T8 is the delay from the
end of link training to backlight on and T9 is the delay from
backlight off until video off. The hardware provides a 'backlight on'
delay, which I'm taking to be T6 + T8 while the VBT provides something
called 'T7', which I'm assuming is s

On the macbook air I'm testing with, this yields a power-up delay of
over 200ms and a power-down delay of over 600ms. It all works now, but
we're frobbing these power controls several times during mode setting,
making the whole process take an awfully long time.

Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-06 08:37:15 -07:00
Keith Packard
f58ff8549e drm/i915: Ensure eDP powered up during DP_SET_POWER operation in dp_prepare
Any call to intel_dp_sink_dpms must ensure that the panel has power so
that the DP_SET_POWER operation will be correctly received. The only
one missing this was in intel_dp_prepare.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2011-10-05 19:56:52 -07:00
Keith Packard
0b5c541b93 drm/i915: Enable eDP panel power during I2C initialization sequence
The DP i2c initialization code does a couple of i2c transactions,
which means that an eDP panel must be powered up.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2011-10-05 19:56:51 -07:00
Keith Packard
8c241fef3e drm/i915: Wrap DP EDID fetch functions to enable eDP panel power
Talking to the eDP DDC channel requires that the panel be powered
up. Wrap both the EDID and modes fetch code with calls to turn the vdd
power on and back off.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2011-10-05 19:56:51 -07:00
Keith Packard
552fb0b7a6 drm/i915: Delay DP i2c initialization until panel power timings are computed
On eDP, DDC requires panel power, but turning that on uses the panel
power sequencing timing values fetch from the DPCD data.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2011-10-05 19:56:50 -07:00
Keith Packard
245e270877 drm/i915: Ensure panel is on during DPMS off
If the panel is already off, we'll need to turn VDD on to execute the
(useless) DPMS off code. Yes, it would be better to just not do any of
this, but correctness, and *then* performance.

Signed-off-by: Keith Packard <keithp@keithp.com>
2011-10-05 19:54:29 -07:00
Keith Packard
bee7eb2da2 drm/i915: Turn force VDD back off when panel running in intel_dp_dpms
The VDD force bit is turned on before touching the panel, but if it
was enabled, there was no call to turn it back off. Add a call.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2011-09-30 16:23:46 -07:00
Keith Packard
97af61f57e drm/i915: Check for eDP inside edp panel on/off funcs
Cleans up code dealing with eDP a bit. Remove redundant checks in
callers

Signed-off-by: Keith Packard <keithp@keithp.com>
2011-09-30 16:23:46 -07:00
Keith Packard
1c0ae80a5e drm/i915: Unlock PCH_PP_CONTROL always
Avoid any question about locked registers by just writing the unlock
pattern with every write to the register.

Signed-off-by: Keith Packard <keithp@keithp.com>
2011-09-30 16:23:45 -07:00
Keith Packard
9b984daec4 drm/i915: Check eDP power when doing aux channel communications
Verify that the eDP VDD is on, either with the panel being on or with
the VDD force-on bit being set.

This demonstrates that in many instances, VDD is not on when needed,
which leads to failed EDID communications.

Signed-off-by: Keith Packard <keithp@keithp.com>
2011-09-30 16:23:45 -07:00
Keith Packard
47f0eb2234 drm/i915: Only use VBT panel mode on eDP if no EDID is found
We're going to assume that EDID is more reliable than the VBT tables
for eDP panels, which is notably true on MacBook machines where the
VBT contains completely bogus data.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2011-09-30 16:23:44 -07:00
Wu Fengguang
e0dac65ed4 drm/i915: pass ELD to HDMI/DP audio driver
Add ELD support for Intel Eaglelake, IbexPeak/Ironlake,
SandyBridge/CougarPoint and IvyBridge/PantherPoint chips.

ELD (EDID-Like Data) describes to the HDMI/DP audio driver the audio
capabilities of the plugged monitor. It's built and passed to audio
driver in 2 steps:

(1) at get_modes time, parse EDID and save ELD to drm_connector.eld[]

(2) at mode_set time, write drm_connector.eld[] to the Transcoder's hw
    ELD buffer and set the ELD_valid bit to inform HDMI/DP audio driver

This patch is tested OK on G45/HDMI, IbexPeak/HDMI and IvyBridge/HDMI+DP.
Test scheme: plug in the HDMI/DP monitor, and run

        cat /proc/asound/card0/eld*

to check if the monitor name, HDMI/DP type, etc. show up correctly.

Minor imperfection: the GEN5_AUD_CNTL_ST/DIP_Port_Select field always
reads 0 (reserved). Without knowing the port number, I worked it around
by setting the ELD_valid bit for ALL the three ports. It's tested to not
be a problem, because the audio driver will find invalid ELD data and
hence rightfully abort, even when it sees the ELD_valid indicator.

Thanks to Zhenyu and Pierre-Louis for a lot of valuable help and testing.

CC: Zhao Yakui <yakui.zhao@intel.com>
CC: Wang Zhenyu <zhenyu.z.wang@intel.com>
CC: Jeremy Bush <contractfrombelow@gmail.com>
CC: Christopher White <c.white@pulseforce.com>
CC: Pierre-Louis Bossart <pierre-louis.bossart@intel.com>
CC: Paul Menzel <paulepanter@users.sourceforge.net>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-09-21 14:52:41 -07:00
Akshay Joshi
0206e353a0 Drivers: i915: Fix all space related issues.
Various issues involved with the space character were generating
warnings in the checkpatch.pl file. This patch removes most of those
warnings.

Signed-off-by: Akshay Joshi <me@akshayjoshi.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-09-19 18:01:47 -07:00
Matthew Garrett
aaa6fd2a00 Not all systems expose a firmware or platform mechanism for changing the backlight intensity on i915, so add native driver support.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Airlie <airlied@linux.ie>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: Sedat Dilek <sedat.dilek@googlemail.com>
Tested-by: Michel Alexandre Salim <salimma@fedoraproject.org>
Tested-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-08-15 12:10:25 -07:00
Keith Packard
3d208bef11 Merge branch 'drm-intel-fixes' into drm-intel-next 2011-08-03 10:41:19 -07:00
Keith Packard
4edd17a25c Revert "drm/i915/dp: Zero the DPCD data before connection probe"
This reverts commit 97cdd71010.

Clearing the dpcd data means that if the fetch fails, any previous
data will be lost. On eDP, this is no fun as we only fetch dpcd at
init time, so the memset will destroy that the next time through.
2011-08-03 10:37:21 -07:00
Jesse Barnes
11bee43ebb drm/i915/dp: wait for previous AUX channel activity to clear
Before initiating a new read or write on the DP AUX channel, wait for
any outstanding activity to complete.  This may happen during normal
retry behavior.  If the wait fails (i.e. after 1ms the AUX channel is
still busy) dump a backtrace to make the caller easier to spot.

v2: use msleep instead, and timeout after 3ms (only ever saw 1 retry
    with msleep in testing)
v3: fix backtrace check to trigger if the 3ms wait times out

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=38136.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-08-01 15:24:18 -07:00
Keith Packard
2c1756b12e Merge branch 'drm-intel-fixes' into drm-intel-next 2011-07-28 16:30:41 -07:00
Keith Packard
d2b996ac69 Revert and fix "drm/i915/dp: remove DPMS mode tracking from DP"
This reverts commit 885a50147f.

We actually *do* need to track DPMS state so that on hotplug, we don't
retrain the link until DPMS is disabled.

However, that code had avery small bug -- it wouldn't set the
dpms_mode at mode set time, and so link retraining would not actually
occur on monitor hotplug until the monitor had gone through a DPMS
off/DPMS on cycle.

Signed-off-by: Keith Packard <keithp@keithp.com>
Tested-by: Andrew Lutomirski <luto@mit.edu>
2011-07-28 16:23:57 -07:00
Keith Packard
59f3e272d7 drm/i915: In intel_dp_init, replace read of DPCD with intel_dp_get_dpcd
Eliminates an open-coded read and also gains the retry behaviour of
intel_dp_get_dpcd, which seems like a good idea.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Adam Jackson <ajax@redhat.com>
2011-07-28 15:47:21 -07:00
Keith Packard
26d61aad7a drm/i915: Rename i915_dp_detect_common to intel_dp_get_dpcd
This describes the function better, allowing it to be used where the
DPCD value is relevant.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Adam Jackson <ajax@redhat.com>
2011-07-28 15:47:21 -07:00
Keith Packard
92fd8fd13b drm/i915: Use dp_detect_common in hotplug helper function
This uses the common dpcd reading routine, i915_dp_detect_common,
instead of open-coding a call to intel_dp_aux_native_read. Besides
reducing duplicated code, this also gains the read retries which
may be necessary when a cable is first plugged back in and the link
needs to be retrained.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Adam Jackson <ajax@redhat.com>
2011-07-28 15:47:20 -07:00
Keith Packard
cf96e46fcd Merge branch 'drm-intel-fixes' into drm-intel-next 2011-07-25 15:22:19 -07:00
Adam Jackson
e85194641b drm/i915/dp: Don't turn CPT DP ports on too early
The docs say the port has to come on in training pattern 1; at this
point, though, ->DP is in normal mode.  The intent here is to wait
until the port is in fact sending data, but that doesn't happen since
we've broken the sequence the hardware expects, and the vblank wait will
time out and kvetch in the log.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-07-25 15:19:19 -07:00
Adam Jackson
81055854d0 drm/i915/dp: Explicitly disable symbol scrambling while training
The DP spec says training patterns 1 and 2 are to be sent non-scrambled,
and the GPU docs claim that happens (or at least, there's no explicit
scrambling control).  But the sink may be confused if we don't
explicitly tell it what we're doing, so play it safe.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
2011-07-25 15:18:33 -07:00