Re: [PATCH v2] drm/msm/dp: account for widebus and yuv420 during mode validation

[Dale Whinham]

On 06/02/2025 19:46, Abhinav Kumar wrote:
> Widebus allows the DP controller to operate in 2 pixel per clock mode.
> The mode validation logic validates the mode->clock against the max
> DP pixel clock. However the max DP pixel clock limit assumes widebus
> is already enabled. Adjust the mode validation logic to only compare
> the adjusted pixel clock which accounts for widebus against the max DP
> pixel clock. Also fix the mode validation logic for YUV420 modes as in
> that case as well, only half the pixel clock is needed.
>
> Fixes: 757a2f36ab09 ("drm/msm/dp: enable widebus feature for display port")
> Fixes: 6db6e5606576 ("drm/msm/dp: change clock related programming for YUV420 over DP")
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> ---
> Changes in v2:
> - move msm_dp_wide_bus_available() to the next line
> - Link to v1: https://lore.kernel.org/r/20250128-dp-widebus-fix-v1-1-b66d2265596b@xxxxxxxxxxx
> ---
>   drivers/gpu/drm/msm/dp/dp_display.c | 11 ++++++-----
>   drivers/gpu/drm/msm/dp/dp_drm.c     |  5 ++++-
>   2 files changed, 10 insertions(+), 6 deletions(-)

This patch fixes a CLOCK_HIGH mode rejection error on the Microsoft 
Surface Pro 11 (OLED panel) which I had previously been working-around 
by raising DP_MAX_PIXEL_CLK_KHZ.

Tested-by: Dale Whinham <daleyo@xxxxxxxxx>

--
Best regards,
Dale