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authorNicholas Kazlauskas <nicholas.kazlauskas@amd.com>2021-11-04 23:52:06 +0300
committerAlex Deucher <alexander.deucher@amd.com>2021-11-10 01:08:00 +0300
commitd82b3266ef88dc10fe0e7031b2bd8ba7eedb7e59 (patch)
treeb43b43584a310c13b9869af6b8adc04c5ef3ed84 /drivers/gpu
parent433e5dec418d026b373d291f97b3996369665f46 (diff)
downloadlinux-d82b3266ef88dc10fe0e7031b2bd8ba7eedb7e59.tar.xz
drm/amd/display: Don't lock connection_mutex for DMUB HPD
[Why] Per DRM spec we only need to hold that lock when touching connector->state - which we do not do in that handler. Taking this locking introduces unnecessary dependencies with other threads which is bad for performance and opens up the potential for a deadlock since there are multiple locks being held at once. [How] Remove the connection_mutex lock/unlock routine and just iterate over the drm connectors normally. The iter helpers implicitly lock the connection list so this is safe to do. DC link access also does not need to be guarded since the link table is static at creation - we don't dynamically add or remove links, just streams. Fixes: e27c41d5b068 ("drm/amd/display: Support for DMUB HPD interrupt handling") Reviewed-by: Jude Shih <shenshih@amd.com> Acked-by: Anson Jacob <Anson.Jacob@amd.com> Tested-by: Daniel Wheeler <daniel.wheeler@amd.com> Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c4
1 files changed, 0 insertions, 4 deletions
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index d0d38d3631dc..6aafcc14b479 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -669,10 +669,7 @@ void dmub_hpd_callback(struct amdgpu_device *adev, struct dmub_notification *not
return;
}
- drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
-
link_index = notify->link_index;
-
link = adev->dm.dc->links[link_index];
drm_connector_list_iter_begin(dev, &iter);
@@ -685,7 +682,6 @@ void dmub_hpd_callback(struct amdgpu_device *adev, struct dmub_notification *not
}
}
drm_connector_list_iter_end(&iter);
- drm_modeset_unlock(&dev->mode_config.connection_mutex);
if (hpd_aconnector)
handle_hpd_irq_helper(hpd_aconnector);