Re: [PATCH v7 11/15] drm/msm/dp: split dp_ctrl_off() into stream and link parts

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] The error code returned by `msm_dp_ctrl_on_pixel_clk()` is ignored in `msm_dp_ctrl_process_phy_test_request()`, allowing execution to proceed even if clock enablement fails.
--

commit 63742fe8cd27d164a8457069750896b0e989b7f3
Author: Abhinav Kumar <quic_abhinavk@quicinc.com>

drm/msm/dp: split dp_ctrl_off() into stream and link parts

This commit splits dp_ctrl_off() into stream and link parts so that for
MST cases we can control the link and pixel parts separately.

> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> index 87c3a5517911f..90fba03de7f0b 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c

[ ... ]

> @@ -2240,7 +2240,8 @@ static int msm_dp_ctrl_process_phy_test_request(struct msm_dp_ctrl_private *ctrl
>  	 * running. Add the global reset just before disabling the
>  	 * link clocks and core clocks.
>  	 */
> -	msm_dp_ctrl_off(&ctrl->msm_dp_ctrl, panel);
> +	msm_dp_ctrl_off_pixel_clk(&ctrl->msm_dp_ctrl);
> +	msm_dp_ctrl_off_link(&ctrl->msm_dp_ctrl, panel);
>  
>  	ret = msm_dp_ctrl_on_link(&ctrl->msm_dp_ctrl, panel);
>  	if (ret) {

[Severity: High]
This isn't a bug introduced by this patch, but while looking at the rest of
msm_dp_ctrl_process_phy_test_request(), the return value from enabling the
pixel clock appears to be completely ignored:

	ret = msm_dp_ctrl_on_pixel_clk(ctrl, pixel_rate);

	msm_dp_ctrl_send_phy_test_pattern(ctrl);

	return 0;

If msm_dp_ctrl_on_pixel_clk() fails to prepare and enable the clock, it
returns a negative error code, but the code still continues execution. Does
processing the PHY test pattern and commanding the DP controller without a
successfully enabled stream clock leave the hardware in an undefined state?
Should we be checking this return value and exiting early on failure?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260609-dp_mstclean-v7-0-ea04113e8233@oss.qualcomm.com?part=11