Re: [PATCH] Revert "drm/bridge: lt9611: Do not generate HFP/HBP/HSA and EOT packet"

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On 02/08/2023 15:07, Marek Vasut wrote:
> On 8/2/23 10:52, Neil Armstrong wrote:
>> This reverts commit [1] to fix display regression on the Dragonboard 845c
>> (SDM845) devboard.
>>
>> There's a mismatch on the real action of the following flags:
>> - MIPI_DSI_MODE_VIDEO_NO_HSA
>> - MIPI_DSI_MODE_VIDEO_NO_HFP
>> - MIPI_DSI_MODE_VIDEO_NO_HBP
>> which leads to a non-working display on qcom platforms.
>>
>> [1] 8ddce13ae696 ("drm/bridge: lt9611: Do not generate HFP/HBP/HSA and 
>> EOT packet")
>>
>> Cc: Marek Vasut <marex@denx.de>
>> Cc: Robert Foss <rfoss@kernel.org>
>> Cc: Jagan Teki <jagan@amarulasolutions.com>
>> Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>> Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
>> Fixes: 8ddce13ae69 ("drm/bridge: lt9611: Do not generate HFP/HBP/HSA 
>> and EOT packet")
>> Reported-by: Amit Pundir <amit.pundir@linaro.org>
>> Link: 
>> https://lore.kernel.org/r/CAMi1Hd0TD=2z_=bcDrht3H_wiLvAFcv8Z-U_r_KUOoeMc6UMjw@mail.gmail.com/
>> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
> 
> This breaks LT9611 operation on i.MX8M Mini/Nano/Plus, so, NAK.
> 
> I am currently using this LT9611 with Linux 6.1.y in production and this 
> is not acceptable. I also believe the correct fix is on the MSM side, 
> not on the LT9611 driver side, since MSM incorrectly implements these 
> flags.

Up to now we saw no proof that MSM incorrectly implements the flags.

-- 
With best wishes
Dmitry