6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mario Limonciello (AMD) superm1@kernel.org
commit 71ad9054c1f241be63f9d11df8cbd0aa0352fe16 upstream.
[Why] When a monitor is booting it's possible that it isn't ready to retrieve link caps and this can lead to an EDID read failure:
``` [drm:retrieve_link_cap [amdgpu]] *ERROR* retrieve_link_cap: Read receiver caps dpcd data failed. amdgpu 0000:c5:00.0: [drm] *ERROR* No EDID read. ```
[How] Rather than msleep once and try a few times, msleep each time. Should be no changes for existing working monitors, but should correct reading caps on a monitor that is slow to boot.
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4672 Reviewed-by: Alex Hung alex.hung@amd.com Signed-off-by: Mario Limonciello (AMD) superm1@kernel.org Signed-off-by: Ivan Lipski ivan.lipski@amd.com Tested-by: Dan Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com (cherry picked from commit 669dca37b3348a447db04bbdcbb3def94d5997cc) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c @@ -1598,12 +1598,13 @@ static bool retrieve_link_cap(struct dc_ status = dpcd_get_tunneling_device_data(link);
dpcd_set_source_specific_data(link); - /* Sink may need to configure internals based on vendor, so allow some - * time before proceeding with possibly vendor specific transactions - */ - msleep(post_oui_delay);
for (i = 0; i < read_dpcd_retry_cnt; i++) { + /* + * Sink may need to configure internals based on vendor, so allow some + * time before proceeding with possibly vendor specific transactions + */ + msleep(post_oui_delay); status = core_link_read_dpcd( link, DP_DPCD_REV,