[PATCH 6.6 01/30] drm/amd/display: Dont use fsleep for PSR exit waits

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>

[ 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@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c | 3 ++-
 drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

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 b87bfecb7755a..a8e79104b684e 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 */
-- 
2.42.0