Re: FAILED: patch "[PATCH] drm/amd/display: Use HW lock mgr for PSR1 when only one eDP" failed to apply to 6.6-stable tree

[Mario Limonciello <mario.limonciello@amd.com>]

On 3/24/2025 10:37, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 6.6-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
> 
> To reproduce the conflict and resubmit, you may use the following commands:
> 
> git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
> git checkout FETCH_HEAD
> git cherry-pick -x acbf16a6ae775b4db86f537448cc466288aa307e
> # <resolve conflicts, build, test, etc.>
> git commit -s
> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025032441-constrain-eastbound-09d8@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
> 
> Possible dependencies:
> 
> 
> 
> thanks,
> 
> greg k-h
> 

Hi,

Here is them missing dependency commit.  Cherry-picking this first will 
let the fix apply cleanly on 6.6.y:

commit bfeefe6ea5f1 ("drm/amd/display: should support dmub hw lock on 
Replay")

Thanks,

> ------------------ original commit in Linus's tree ------------------
> 
>  From acbf16a6ae775b4db86f537448cc466288aa307e Mon Sep 17 00:00:00 2001
> From: Mario Limonciello <mario.limonciello@amd.com>
> Date: Fri, 7 Mar 2025 15:55:20 -0600
> Subject: [PATCH] drm/amd/display: Use HW lock mgr for PSR1 when only one eDP
> 
> [WHY]
> DMUB locking is important to make sure that registers aren't accessed
> while in PSR.  Previously it was enabled but caused a deadlock in
> situations with multiple eDP panels.
> 
> [HOW]
> Detect if multiple eDP panels are in use to decide whether to use
> lock. Refactor the function so that the first check is for PSR-SU
> and then replay is in use to prevent having to look up number
> of eDP panels for those configurations.
> 
> Fixes: f245b400a223 ("Revert "drm/amd/display: Use HW lock mgr for PSR1"")
> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3965
> Reviewed-by: ChiaHsuan Chung <chiahsuan.chung@amd.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
> Signed-off-by: Alex Hung <alex.hung@amd.com>
> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> (cherry picked from commit ed569e1279a3045d6b974226c814e071fa0193a6)
> Cc: stable@vger.kernel.org
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/dce/dmub_hw_lock_mgr.c b/drivers/gpu/drm/amd/display/dc/dce/dmub_hw_lock_mgr.c
> index bf636b28e3e1..6e2fce329d73 100644
> --- a/drivers/gpu/drm/amd/display/dc/dce/dmub_hw_lock_mgr.c
> +++ b/drivers/gpu/drm/amd/display/dc/dce/dmub_hw_lock_mgr.c
> @@ -69,5 +69,16 @@ bool should_use_dmub_lock(struct dc_link *link)
>   	if (link->replay_settings.replay_feature_enabled)
>   		return true;
>   
> +	/* only use HW lock for PSR1 on single eDP */
> +	if (link->psr_settings.psr_version == DC_PSR_VERSION_1) {
> +		struct dc_link *edp_links[MAX_NUM_EDP];
> +		int edp_num;
> +
> +		dc_get_edp_links(link->dc, edp_links, &edp_num);
> +
> +		if (edp_num == 1)
> +			return true;
> +	}
> +
>   	return false;
>   }
>