[PATCH] drm/msm/dp: allow voltage swing / pre emphasis of 3

[Abhinav Kumar]

Hi Doug

On 3/29/2024 4:07 PM, Doug Anderson wrote:
> Hi,
> 
> On Sat, Feb 3, 2024 at 5:47 AM Dmitry Baryshkov
> <dmitry.baryshkov at linaro.org> wrote:
>>
>> Both dp_link_adjust_levels() and dp_ctrl_update_vx_px() limit swing and
>> pre-emphasis to 2, while the real maximum value for the sum of the
>> voltage swing and pre-emphasis is 3. Fix the DP code to remove this
>> limitation.
>>
>> Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support")
>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
>> ---
>>   drivers/gpu/drm/msm/dp/dp_ctrl.c |  6 +++---
>>   drivers/gpu/drm/msm/dp/dp_link.c | 22 +++++++++++-----------
>>   drivers/gpu/drm/msm/dp/dp_link.h | 14 +-------------
>>   3 files changed, 15 insertions(+), 27 deletions(-)
> 
> What ever happened with this patch? It seemed important so I've been
> trying to check back on it, but it seems to still be in limbo. I was
> assuming that (maybe?) Abhinav would check things against the hardware
> documentation and give it a Reviewed-by and then it would land...
> 
> -Doug

The issue for which this patch was originally made (DP link training 
issue on x1e80100) was not getting fixed by this patch.

That one turned out as actually a PLL locking issue. So this kind of 
went off the radar as it was not immediately needed to fix anything.

I will wait for Kuogee's response on this patch. He was OOO entire Feb 
so this got missed.