Re: [PATCH 0/2] drm/tilcdc drm/i2c/tda998x workaround for sync issues on TI SoC

[Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>]

On 07/25/2013 09:32 PM, Rob Clark wrote:
> On Thu, Jul 25, 2013 at 2:32 PM, Darren Etheridge <detheridge@ti.com> wrote:
[...]
>> This patch set inverts the hsync signal coming from the tilcdc so the NXP
>> is kept happy and then shifts the output to the right to compensate for the
>> sync timing issues.  Display modes from the NXP have been verified using a
>> HDMI analyzer and are reporting correct timings at the output stage.
>>
>> Hopefully this will allow the dove/tda driver changes to progress now that
>> were blocked as per this discussion:
>> http://lists.freedesktop.org/archives/dri-devel/2013-July/040900.html
>>
>
> Good find Darren!  The patches look good to me from a quick review.
> It would be good to get a tested-by from someone on cubox, but it is
> good that we finally found the issue so that we can unblock further
> tda998x development.

Darren,

I now fully understand the issues of AM335x's LCD controller and your
fix for it. I suggest to clarify the comments you added to tilcdc to
allow others to understand it more quickly.

Actually, the LCD controller always aligns vsync to the second edge
of hsync, which will never give VESA-compliant sync. The (elegant)
workaround you are proposing is to align both rising edges, so at
least TDA998x can sync on those with some hskew added. Lucky you that
it ignores hsync length but only looks for rising HS/VS edges ;)

Should we prepare a new patch set comprising the following patches?

Russell King:
drm/i2c: nxp-tda998x: fix EDID reading on TDA19988 devices
drm/i2c: nxp-tda998x: ensure VIP output mux is properly set
drm/i2c: nxp-tda998x: fix npix/nline programming
drm/i2c: nxp-tda998x: prepare for video input configuration
drm/i2c: nxp-tda998x: add video and audio input configuration

Sebastian Hesselbarth:
drm/i2c: tda998x: fix sync generation and calculation

Darren Etheridge:
drm/i2c/tda998x prepare for tilcdc sync workaround
drm/tilcdc fixup mode to workaound sync for tda998x

Or do we keep them separated and possibly resend them if David cannot
find them anymore?

Sebastian