5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Imre Deak imre.deak@intel.com
This reverts commit 2402adce8da4e7396b63b5ffa71e1fa16e5fe5c4 which is commit a40c5d727b8111b5db424a1e43e14a1dcce1e77f upstream.
The upstream commit a40c5d727b8111b5db424a1e43e14a1dcce1e77f ("drm/dp: Change AUX DPCD probe address from DPCD_REV to LANE0_1_STATUS") the reverted commit backported causes a regression, on one eDP panel at least resulting in display flickering, described in detail at the Link: below. The issue fixed by the upstream commit will need a different solution, revert the backport for now.
Cc: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Cc: Sasha Levin sashal@kernel.org Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14558 Signed-off-by: Imre Deak imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/drm_dp_helper.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -280,7 +280,7 @@ ssize_t drm_dp_dpcd_read(struct drm_dp_a * We just have to do it before any DPCD access and hope that the * monitor doesn't power down exactly after the throw away read. */ - ret = drm_dp_dpcd_access(aux, DP_AUX_NATIVE_READ, DP_LANE0_1_STATUS, buffer, + ret = drm_dp_dpcd_access(aux, DP_AUX_NATIVE_READ, DP_DPCD_REV, buffer, 1); if (ret != 1) goto out;