Retry the dpcd fetch several times. Some eDP panels fail several times before the fetch is successful.
bug: https://bugs.freedesktop.org/show_bug.cgi?id=73530 Ported from radeon. Reviewed-by: Christian König <christian.koenig at amd.com> Signed-off-by: Alex Deucher <alexander.deucher at amd.com> --- drivers/gpu/drm/amd/amdgpu/atombios_dp.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c index d54c4b8..9ba0a7d 100644 --- a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c +++ b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c @@ -358,19 +358,21 @@ int amdgpu_atombios_dp_get_dpcd(struct amdgpu_connector *amdgpu_connector) { struct amdgpu_connector_atom_dig *dig_connector = amdgpu_connector->con_priv; u8 msg[DP_DPCD_SIZE]; - int ret; + int ret, i; - ret = drm_dp_dpcd_read(&amdgpu_connector->ddc_bus->aux, DP_DPCD_REV, msg, - DP_DPCD_SIZE); - if (ret > 0) { - memcpy(dig_connector->dpcd, msg, DP_DPCD_SIZE); + for (i = 0; i < 7; i++) { + ret = drm_dp_dpcd_read(&amdgpu_connector->ddc_bus->aux, DP_DPCD_REV, msg, + DP_DPCD_SIZE); + if (ret == DP_DPCD_SIZE) { + memcpy(dig_connector->dpcd, msg, DP_DPCD_SIZE); - DRM_DEBUG_KMS("DPCD: %*ph\n", (int)sizeof(dig_connector->dpcd), - dig_connector->dpcd); + DRM_DEBUG_KMS("DPCD: %*ph\n", (int)sizeof(dig_connector->dpcd), + dig_connector->dpcd); - amdgpu_atombios_dp_probe_oui(amdgpu_connector); + amdgpu_atombios_dp_probe_oui(amdgpu_connector); - return 0; + return 0; + } } dig_connector->dpcd[0] = 0; return -EINVAL; -- 1.8.3.1
