On 5/7/2025 9:38 AM, Jessica Zhang wrote:
Filter out modes that have a clock rate greater than the max core clock
rate when adjusted for the perf clock factor

This is especially important for chipsets such as QCS615 that have lower
limits for the MDP max core clock.

Since the core CRTC clock is at least the mode clock (adjusted for the
perf clock factor) [1], the modes supported by the driver should be less
than the max core clock rate.

[1] 
https://elixir.bootlin.com/linux/v6.12.4/source/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c#L83

Reviewed-by: Dmitry Baryshkov <[email protected]>
Signed-off-by: Jessica Zhang <[email protected]>
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Hi. This patch effectively filters out the 3840x2160@120Hz mode on SC8280XP CRD. The calculated adjusted_mode_clk is 623700, which slightly exceeds the supported max core clock of 600000.

However, 4K 120Hz works flawlessly with the limit removed on this platform. I even tried connecting two 4K 120Hz displays, and they can work properly simultaneously. Is it possible to bring back support for this mode, or adjust the limits?


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Best regards,
Xilin Wu <[email protected]>

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