Commit Graph

2524 Commits

Author SHA1 Message Date
Alex Deucher
2581afccad drm/radeon/kms: make sure HPD is set to NONE on analog-only connectors
HPD is digital only.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 14:23:57 +10:00
Alex Deucher
e0a2ca7375 drm/radeon/kms: make sure rio_mem is valid before unmapping it
If we were not able to map the io bar in device init, don't attempt
to unmap it in device fini.  All radeons should have a io bar, so
I doubt this would ever trigger, but just to be on the safe side...

Pointed out by: Alberto Milone <alberto.milone@canonical.com>
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 14:21:37 +10:00
Dave Airlie
ab9e1f5966 drm/radeon: add basic zmask/hiz support (v4)
This interface allows userspace to request hyperz support, it probably
needs more locking, and really reporting that you can have hyperz is racy
since someone else might get it before you do.

v2: modify so we pass 0 valued packets to let DDX/r300c keep working.
also fixed incorrect 0x4f1c reference.

v3: fixup zb_bw_cntl so older drivers keep working

v4: add locking, fixup SC_HYPERZ_EN - patch stream to disable hiz

Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 11:54:26 +10:00
Dave Airlie
d9fdaafbe9 drm/radeon/kms: move a bunch of modesetting debug to correct debug usage.
This migrates a bunch of DRM_DEBUG->DRM_DEBUG_KMS so we can get more modesetting related info without all the other ioctl handling easily.

Also the PM code moves to DRM_DEBUG_DRIVER mostly.

Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:47:07 +10:00
Dave Airlie
d6486813d2 Merge remote branch 'nouveau/for-airlied' of ../drm-nouveau-next into drm-core-next
* 'nouveau/for-airlied' of ../drm-nouveau-next: (77 commits)
  drm/nouveau: set TASK_(UN)INTERRUPTIBLE before schedule_timeout()
  drm/nv50: fix some not-error error messages
  drm/nouveau: introduce gpio engine
  drm/nv50: correct wait condition for instmem flush
  drm/nouveau: Fix TV-out detection on unposted cards lacking a usable DCB table.
  drm/nouveau: Get rid of the remaining VGA CRTC locking.
  drm/nouveau: Move display init to a new nouveau_engine.
  drm/nouveau: Put back the old 2-messages I2C slave test.
  drm/nouveau: Reset AGP before running the init scripts.
  drm/nv30: Init the PFB+0x3xx memory timing regs.
  drm/nouveau: disable hotplug detect around DP link training
  drm/nv50: add function to control GPIO IRQ reporting
  drm/nouveau: add nv_mask register accessor
  drm/nouveau: fix build without CONFIG_ACPI
  drm/nouveau: Reset CRTC owner to 0 before BIOS init.
  drm/nouveau: No need to lock/unlock the VGA CRTC regs all the time.
  drm/nouveau: Remove useless CRTC_OWNER logging.
  drm/nouveau: Add some generic I2C gadget detection code.
  drm/i2c/ch7006: Don't assume that the specified config points to static memory.
  drm/nv04-nv3x: Implement init-compute-mem.
  ...

Conflicts:
	drivers/gpu/drm/nouveau/nouveau_bios.c
2010-08-02 10:31:47 +10:00
Dave Airlie
7827627107 Merge branch 'drm-radeon-next' of ../drm-radeon-next into drm-core-next
* 'drm-radeon-next' of ../drm-radeon-next: (333 commits)
  drm/radeon/kms: trivial code style fixes for audio
  drm/radeon: remove viewport transform from r6xx/r7xx blit emit
  drm/radeon: group r6xx/r7xx newly sequential blit state
  drm/radeon: reorder r6xx/r7xx blit state emit to make more regs sequential
  drm/radeon: r6xx/r7xx move vport clipping to a single packet
  drm/radeon: group r6xx/r7xx sequential blit state
  drm/radeon: remove duplicate state emit in r6xx/r7xx blit
  drm/radeon: add comments to r6xx/r7xx blit state
  drm/radeon/kms/r7xx: add workaround for hw issue with HDP flush
  drm/radeon/kms: remove rs4xx gart limit
  drm: radeon: fix sign bug
  drm/radeon/kms: check/restore sanity before doing anything else with GPU.
  drm/radeon: fall back to GTT if bo creation/validation in VRAM fails.
  drm/radeon/kms: add ioport register access
  drm/radeon/kms: enable HDMI audio on RS600/RS690/RS740
  drm/radeon/kms: track audio engine state, do not use not setup timer
  drm/radeon/kms/r6xx+: add query for tile config (v2)
  drm/radeon/kms: fix CS alignment checking for tiling (v2)
  drm/radeon/kms: add tiling support to the cs checker for r6xx/r7xx
  drm/radeon/kms: Add crtc tiling setup support for evergreen
  ...
2010-08-02 10:24:46 +10:00
Francisco Jerez
e190bfe568 drm: Import driver for the sil164 I2C TMDS transmitter.
sil164 transmitters are used for DVI outputs on Intel/nvidia and ATI setups.

So far only nouveau can use this driver.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Tested-by: Patrice Mandin <patmandin@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:21:13 +10:00
Nicolas Kaiser
a7b98b6748 drm/sis: fixed brace and spacing coding style issues
Fixed brace and spacing coding style issues.

Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:18:17 +10:00
Nicolas Kaiser
bc5e9d6a22 drm/r128: fixed brace and spacing coding style issues
Fixed brace and spacing coding style issues.

Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:17:48 +10:00
Nicolas Kaiser
f2b2cb790e drm/mga: fixed brace, macro and spacing coding style issues
Fixed brace, macro and spacing coding style issues.

Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:17:36 +10:00
Nicolas Kaiser
58c1e85af3 drm/via: fixed coding style issues, simplified return
Fixed brace, macro and spacing coding style issues.
Simplified
 -if (ret) return ret;
 -return 0;
 +return ret;

Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:17:23 +10:00
Rafał Miłecki
219de62a16 drm/radeon/kms: trivial code style fixes for audio
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:17:10 +10:00
Nicolas Kaiser
5649911316 drm/i830: fixed brace and spacing coding style issues
Fixed brace and spacing coding style issues.

Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:15:54 +10:00
Nicolas Kaiser
aca791c28a drm/i810: fixed coding style issues
Fixed brace, macro and spacing coding style issues, and a C99 comment.

Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:15:41 +10:00
Chris Wilson
6e35023ffa drm: Free devname along with master->unique
The device name is tightly coupled and created at the same time as the
master->unique address, so we need to free it with the master. Currently
we overwrite it each time we create a new master:

unreferenced object 0xe32c54b0 (size 32):
  comm "Xorg", pid 1455, jiffies 4294721798 (age 3196.879s)
  hex dump (first 32 bytes):
    69 39 31 35 40 70 63 69 3a 30 30 30 30 3a 30 30  i915@pci:0000:00
    3a 30 32 2e 30 00 6b 6b 6b 6b 6b 6b 6b 6b 6b a5  :02.0.kkkkkkkkk.
  backtrace:
    [<c04e5657>] create_object+0x124/0x1f1
    [<c07cf0f0>] kmemleak_alloc+0x4c/0x90
    [<c04db84c>] __kmalloc+0x155/0x175
    [<f8316665>] drm_setversion+0x11d/0x1b1 [drm]
    [<f83148d4>] drm_ioctl+0x29a/0x356 [drm]
    [<c04f27c4>] vfs_ioctl+0x33/0x91
    [<c04f31cf>] do_vfs_ioctl+0x46b/0x496
    [<c04f3240>] sys_ioctl+0x46/0x66
    [<c040325f>] sysenter_do_call+0x12/0x38
    [<ffffffff>] 0xffffffff

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:14:30 +10:00
Chris Wilson
ddd3d069c0 drm: Free the idr layers before calling idr_destroy()
/* A typical clean-up sequence for objects stored in an idr tree, will
 * use idr_for_each() to free all objects, if necessary, then
 * idr_remove_all() to remove all ids, and idr_destroy() to free
 * up the cached idr_layers.
 */

We were missing the vital idr_rmove_all() step and so were leaking
the used layers for every dri client:

unreferenced object 0xf32133c0 (size 148):
  comm "plymouthd", pid 131, jiffies 4294678490 (age 2308.030s)
  hex dump (first 32 bytes):
    04 00 00 00 00 00 00 00 00 00 00 00 00 40 19 f3  .............@..
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<c04e5657>] create_object+0x124/0x1f1
    [<c07cf100>] kmemleak_alloc+0x4c/0x90
    [<c04db6a9>] kmem_cache_alloc+0xee/0x13c
    [<c05c3d25>] idr_pre_get+0x24/0x61
    [<f8315c9c>] drm_gem_handle_create+0x27/0x7f [drm]
    [<f89925b2>] i915_gem_create_ioctl+0x4f/0x71 [i915]
    [<f83148ac>] drm_ioctl+0x272/0x356 [drm]
    [<c04f27c4>] vfs_ioctl+0x33/0x91
    [<c04f31cf>] do_vfs_ioctl+0x46b/0x496
    [<c04f3240>] sys_ioctl+0x46/0x66
    [<c040325f>] sysenter_do_call+0x12/0x38
    [<ffffffff>] 0xffffffff

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=15803

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:13:56 +10:00
Kulikov Vasiliy
05991110cf drm/nouveau: set TASK_(UN)INTERRUPTIBLE before schedule_timeout()
set_current_state() is called only once before the first iteration.
After return from schedule_timeout() current state is TASK_RUNNING. If
we are going to wait again, set_current_state() must be called.

Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2010-08-02 10:12:26 +10:00
Chris Wilson
c39721c775 drm/vmgfx: operation on ‘par->dirty.y1’ may be undefined
Trivial fix to set y1 = y2 = 0.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jakob Bornecrantz <jakob@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:12:21 +10:00
Alex Deucher
b417cc117a drm/radeon: remove viewport transform from r6xx/r7xx blit emit
We aren't using it, so no need.  Save additional dwords.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:07:48 +10:00
Alex Deucher
43a7d2d104 drm/radeon: group r6xx/r7xx newly sequential blit state
group state that is emitted sequentially into fewer packets.
This saves a number of dwords.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:07:39 +10:00
Alex Deucher
d0623a3e74 drm/radeon: reorder r6xx/r7xx blit state emit to make more regs sequential
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:07:24 +10:00
Alex Deucher
363c6a16e3 drm/radeon: r6xx/r7xx move vport clipping to a single packet
Saves lots of dwords in blit emit

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:07:09 +10:00
Alex Deucher
eb544433c3 drm/radeon: group r6xx/r7xx sequential blit state
group state that is emitted sequentially into fewer packets.
This saves a number of dwords.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:06:55 +10:00
Alex Deucher
7fc8878c33 drm/radeon: remove duplicate state emit in r6xx/r7xx blit
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:06:44 +10:00
Alex Deucher
8c119e9c3b drm/radeon: add comments to r6xx/r7xx blit state
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:06:32 +10:00
Alex Deucher
812d046915 drm/radeon/kms/r7xx: add workaround for hw issue with HDP flush
Use of HDP_*_COHERENCY_FLUSH_CNTL can cause a hang in certain
situations.  Add workaround.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:06:18 +10:00
Alex Deucher
833ee5c4ab drm/radeon/kms: remove rs4xx gart limit
We used to limit the rs4xx gart aperture to 32 MB, but I suspect
that was due to not meeting the alignment requirements of the
aperture.  This patch should only be applied after:
"drm/radeon/kms: fix gtt MC base alignment on rs4xx/rs690/rs740 asics"
has been applied.

This patch should probably soak for a bit in d-r-t.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:06:01 +10:00
Dave Airlie
d656ae53f6 Merge tag 'v2.6.35-rc6' into drm-radeon-next
Need this to avoid conflicts with future radeon fixes
2010-08-02 10:05:24 +10:00
Dan Carpenter
167ffc44ca drm: radeon: fix sign bug
The "error" variable is unsigned so it's never less than zero.  I
changed it to check if (freq < current_freq) directly.

"best_error" is also unsigned so "best_error - 100" could be a large
number instead of a negative.  Since "error" is unsigned it is never
less than a negative and so the cases where "best_error" is less than or
equal to 100 are false.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:10 +10:00
Dave Airlie
4c712e6c7e drm/radeon/kms: check/restore sanity before doing anything else with GPU.
On systems using kexec, the new kernel is booted straight from the old kernel, without any warning to the graphics driver. So the GPU is basically left as-is in a running state, however the CPU side is completly reset.

Without stating the saneness of anyone using kexec on live systems, we should at least try not to crash the GPU. This patch resets 3 registers to 0 that could cause bad things to happen to the running system.

This allows kexec to work on a Power6/RN50 system.

Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:09 +10:00
Michel Dänzer
e376573f72 drm/radeon: fall back to GTT if bo creation/validation in VRAM fails.
This fixes a problem where on low VRAM cards we'd run out of space for validation.

[airlied: Tested on my M7, Thinkpad T42, compiz works with no problems.]

Signed-off-by: Michel Dänzer <daenzer@vmware.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:08 +10:00
Alex Deucher
351a52a241 drm/radeon/kms: add ioport register access
This is required for the NB_MISC regs on rs780/rs880 which
means HDMI/DVI/DP ports using PCIEPHY won't work without
it. It might also help with s/r (asic init) issues on other
atombios cards.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=28774
and similar issues reported by Alberto Milone.

[airlied: Squash io fix patch]

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Tested-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:07 +10:00
Rafał Miłecki
fe50ac78a6 drm/radeon/kms: enable HDMI audio on RS600/RS690/RS740
We will need method of selecting encoder that should receive HDMI block. For
now we assign HDMI block to first enabled encoder. Hopefully there are not many
RS6x0 chips with two digital encoders.

[airlied: add RS740 checks as per Alex suggestion.]

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:06 +10:00
Rafał Miłecki
7eea7e9eea drm/radeon/kms: track audio engine state, do not use not setup timer
This is needed to enable audio support on devices using polling. In case user
decides to disable audio (module parameter) we still will try to use timer in
r600_audio_enable_polling. This would lead to BUG in kernel/timer.c.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:06 +10:00
Alex Deucher
e7aeeba6a8 drm/radeon/kms/r6xx+: add query for tile config (v2)
Userspace needs this information to access tiled
buffers via the CPU.

v2: rebased on evergreen accel changes

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:05 +10:00
Alex Deucher
40e2a5c15d drm/radeon/kms: fix CS alignment checking for tiling (v2)
Covers depth, cb, and textures. Hopefully I got this right.

v2: - fix bugs:
      https://bugs.freedesktop.org/show_bug.cgi?id=28327
      https://bugs.freedesktop.org/show_bug.cgi?id=28381
    - use ALIGNED(), IS_ALIGNED() macros

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:04 +10:00
Alex Deucher
7f81337720 drm/radeon/kms: add tiling support to the cs checker for r6xx/r7xx
Check for relocs for DB_DEPTH_INFO, CB_COLOR*_INFO, and texture
resources.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:03 +10:00
Alex Deucher
97d6632853 drm/radeon/kms: Add crtc tiling setup support for evergreen
Needed for scanning out of a tiled buffer.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:02 +10:00
Alex Deucher
40c4ac1c19 drm/radeon/kms: Add crtc tiling setup support for r6xx/r7xx
Needed for scanning out of a tiled buffer.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:01 +10:00
Alex Deucher
21a8122ad3 drm/radeon/kms: add support for internal thermal sensors (v3)
rv6xx/rv7xx/evergreen families supported; older asics did
not have an internal thermal sensor.

Note, not all oems use the internal thermal sensor, so it's
only exposed in cases where it is used.

Note also, that most laptops use an oem specific ACPI solution for
GPU thermal information rather than using the internal thermal
sensor directly.

v2: export millidegrees celsius, use hwmon device properly.
v3: fix Kconfig

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 10:00:00 +10:00
Alberto Milone
d7a2952f1a drm/radeon: Add support for the ATIF ACPI method to the radeon driver
By calling the ATIF method in the radeon driver we can make sure
that hotkeys such as the video switch key emit ACPI events when
pressed.

agd5f: fix warning

Signed-off-by: Alberto Milone <alberto.milone@canonical.com>
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 09:59:59 +10:00
Alex Deucher
9bd7ef5f5a drm/radeon/kms/atom: bump atom loop timeout from 1 sec to 5 secs
Some tables have delays that can cause the timeout to hit
even when not intended.

Should fix:
https://bugs.freedesktop.org/show_bug.cgi?id=27744
and related bugs.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 09:59:58 +10:00
Alex Deucher
4ce9198ecf drm/radeon/kms: minor driver cleanups
- Make the logic in r100_pll_errata_after_index() match the other
errata functions
- Use rdev->family rather than rdev->flags & RADEON_FAMILY_MASK for kms
- replace rn50 check using ids with ASIC_IS_RN50 convenience macro

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-08-02 09:59:57 +10:00
Ben Skeggs
0ccb3a75fe drm/nv50: fix some not-error error messages
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2010-07-26 11:44:02 +10:00
Ben Skeggs
ee2e013131 drm/nouveau: introduce gpio engine
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2010-07-26 11:43:57 +10:00
Ben Skeggs
bf563a6b7c drm/nv50: correct wait condition for instmem flush
Reported-by: Marcin Kościelnicki <koriakin@0x04.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2010-07-26 11:43:52 +10:00
Francisco Jerez
c04c5b1da1 drm/nouveau: Fix TV-out detection on unposted cards lacking a usable DCB table.
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2010-07-26 11:43:48 +10:00
Francisco Jerez
946fd35f88 drm/nouveau: Get rid of the remaining VGA CRTC locking.
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2010-07-26 11:43:43 +10:00
Francisco Jerez
c88c2e0631 drm/nouveau: Move display init to a new nouveau_engine.
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2010-07-26 11:43:36 +10:00
Francisco Jerez
f1feda70b5 drm/nouveau: Put back the old 2-messages I2C slave test.
I was hoping we could detect I2C devices at a given address without
actually writing data into them, but apparently some DDC slaves get
confused with 0-bytes transactions. Put the good old test back.

Reported-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2010-07-26 11:43:31 +10:00