[PATCH] Fix GM965 TV out regression

[PATCH] Fix GM965 TV out regression

[Robert Lowery]

I recently upgraded to ubuntu 12.04 and noticed the TV out no longer works
with kernel 3.2.0.

Tracing back through old kernels, I found the last working kernel was 2.6.35.

Now 4 years ago I fixed a similar issue in the user space intel driver by
waiting for vblank after writing to the TV_CTL register via
http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/commit/src/i830_tv.c?id=1142be53eb8d2ee8a9b60ace5d49f0ba27332275

Low and behold, it appears 2 years later this same issue was reintroduced
in kernel 2.6.36 and has led to some very unhappy users eg
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/763688

Could someone please apply the following which I have confirmed re-fixes
the issue for my TV output via component video connection.

--- intel_tv.c.orig	2012-05-19 16:32:21.000000000 +1000
+++ intel_tv.c	2012-05-19 16:33:23.000000000 +1000
@@ -1186,6 +1186,9 @@ intel_tv_detect_type(struct intel_tv *in
 	I915_WRITE(TV_DAC, save_tv_dac & ~TVDAC_STATE_CHG_EN);
 	I915_WRITE(TV_CTL, save_tv_ctl);

+	intel_wait_for_vblank(intel_tv->base.base.dev,
+			      to_intel_crtc(intel_tv->base.base.crtc)->pipe);
+
 	/* Restore interrupt config */
 	if (connector->polled & DRM_CONNECTOR_POLL_HPD) {
 		spin_lock_irqsave(&dev_priv->irq_lock, irqflags);

Re: [PATCH] Fix GM965 TV out regression

[Daniel Vetter]

On Sat, May 19, 2012 at 04:52:10PM +1000, Robert Lowery wrote:
> I recently upgraded to ubuntu 12.04 and noticed the TV out no longer works
> with kernel 3.2.0.
> 
> Tracing back through old kernels, I found the last working kernel was 2.6.35.
> 
> Now 4 years ago I fixed a similar issue in the user space intel driver by
> waiting for vblank after writing to the TV_CTL register via
> http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/commit/src/i830_tv.c?id=1142be53eb8d2ee8a9b60ace5d49f0ba27332275
> 
> Low and behold, it appears 2 years later this same issue was reintroduced
> in kernel 2.6.36 and has led to some very unhappy users eg
> https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/763688
> 
> Could someone please apply the following which I have confirmed re-fixes
> the issue for my TV output via component video connection.

Nice piece of diggin through code! A few minor nitpicks on the patch:
- sob-line is missing (see Documentation/SubmittingPatches)
- are there any other people who have tested this patch? If so, please
  include them in the patch with a

  Tested-by: Name <mail@server>

Rodrigo, can you please check this patch with the docs and maybe quickly
run it?

Thanks, Daniel
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48

Re: [PATCH] Fix GM965 TV out regression

[Chris Wilson]

On Sat, 19 May 2012 20:38:20 +0200, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Sat, May 19, 2012 at 04:52:10PM +1000, Robert Lowery wrote:
> > Could someone please apply the following which I have confirmed re-fixes
> > the issue for my TV output via component video connection.

> Rodrigo, can you please check this patch with the docs and maybe quickly
> run it?

The patch looks reasonable (just lacking a POSTING_READ prior to the
wait as that is not guaranteed by the wait). My guess would be that we
need a vblank to be sure that the writes latched and we indeed switched
off the detection mode prior to turning the pipe off. Not sure how that
results in ghost TV detection, and so it would be good to capture any
final explanation as a code comment to make sure that the wait isn't
deleted again in future.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Re: [PATCH] Fix GM965 TV out regression

[Robert Lowery]

> On Sat, May 19, 2012 at 04:52:10PM +1000, Robert Lowery wrote:
>> I recently upgraded to ubuntu 12.04 and noticed the TV out no longer
>> works
>> with kernel 3.2.0.
>>
>> Tracing back through old kernels, I found the last working kernel was
>> 2.6.35.
>>
>> Now 4 years ago I fixed a similar issue in the user space intel driver
>> by
>> waiting for vblank after writing to the TV_CTL register via
>> http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/commit/src/i830_tv.c?id=1142be53eb8d2ee8a9b60ace5d49f0ba27332275
>>
>> Low and behold, it appears 2 years later this same issue was
>> reintroduced
>> in kernel 2.6.36 and has led to some very unhappy users eg
>> https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/763688
>>
>> Could someone please apply the following which I have confirmed re-fixes
>> the issue for my TV output via component video connection.
>
> Nice piece of diggin through code! A few minor nitpicks on the patch:
> - sob-line is missing (see Documentation/SubmittingPatches)
> - are there any other people who have tested this patch? If so, please
>   include them in the patch with a
>
>   Tested-by: Name <mail@server>

Signed-off-by: Robert Lowery <rglowery@exemail.com.au>

I'm not aware of anyone else that has tested this patch as yet.

>
> Rodrigo, can you please check this patch with the docs and maybe quickly
> run it?
>
> Thanks, Daniel
> --
> Daniel Vetter
> Mail: daniel@ffwll.ch
> Mobile: +41 (0)79 365 57 48
>