Patch "drm/amd/display: Don't use fsleep for PSR exit waits" has been added to the 6.5-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/amd/display: Don't use fsleep for PSR exit waits

to the 6.5-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-amd-display-don-t-use-fsleep-for-psr-exit-waits.patch
and it can be found in the queue-6.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit dbad77a4bde800ff79148edd16910f09122f562e
Author: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
Date:   Wed Sep 27 15:06:41 2023 -0400

    drm/amd/display: Don't use fsleep for PSR exit waits
    
    [ Upstream commit 79df45dc4bfb13d9bd3a75338b9d9dab948be3d6 ]
    
    [Why]
    These functions can be called from high IRQ levels and the OS will hang
    if it tries to use a usleep_highres or a msleep.
    
    [How]
    Replace the fsleep with a udelay.
    
    Reviewed-by: Aric Cyr <aric.cyr@xxxxxxx>
    Acked-by: Tom Chung <chiahsuan.chung@xxxxxxx>
    Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
    Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
    Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c b/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
index 63009db8b5a72..d156eeef466f9 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
@@ -586,7 +586,8 @@ static void dcn10_dmcu_set_psr_enable(struct dmcu *dmcu, bool enable, bool wait)
 				if (state == PSR_STATE0)
 					break;
 			}
-			fsleep(500);
+			/* must *not* be fsleep - this can be called from high irq levels */
+			udelay(500);
 		}
 
 		/* assert if max retry hit */
diff --git a/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c b/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c
index 0f24b6fbd2201..4704c9c85ee6f 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c
@@ -216,7 +216,8 @@ static void dmub_psr_enable(struct dmub_psr *dmub, bool enable, bool wait, uint8
 					break;
 			}
 
-			fsleep(500);
+			/* must *not* be fsleep - this can be called from high irq levels */
+			udelay(500);
 		}
 
 		/* assert if max retry hit */