From: Arindam Nath Date: Wed, 26 Apr 2017 12:09:56 +0000 (+0530) Subject: drm/amd/display: fix resume hang because of DP short pulse X-Git-Tag: v4.15-rc1~56^2~23^2~536 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=03ea364c8e156b2bb5c64465718e8ebd75e3df22;p=linux.git drm/amd/display: fix resume hang because of DP short pulse There is a hard hang observed during resume from S3 when the system receives a DP short pulse interrupt. This is because there are two code paths contending for GPIO access for AUX channel transactions. One such path is through amdgpu_dm_display_resume() function which is invoked from the regular system resume code path. The other path is through handle_hpd_rx_irq(), which is invoked in response to system receiving DP short pulse interrupt. handle_hpd_rx_irq() guards against conflicting GPIO access using hpd_lock, but the GPIO access from amdgpu_dm_display_resume() remains unguarded. This patch makes sure we use hpd_lock inside amdgpu_dm_display_resume() to avoid race conditions for GPIO access. Signed-off-by: Arindam Nath Signed-off-by: Alex Deucher --- 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 84995a48ec61..74e32246ff30 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -580,9 +580,11 @@ int amdgpu_dm_display_resume(struct amdgpu_device *adev ) if (aconnector->mst_port) continue; + mutex_lock(&aconnector->hpd_lock); dc_link_detect(aconnector->dc_link, false); aconnector->dc_sink = NULL; amdgpu_dm_update_connector_after_detect(aconnector); + mutex_unlock(&aconnector->hpd_lock); } /* Force mode set in atomic comit */