[PATCH 6.6.y] Revert "drm/dp: Change AUX DPCD probe address from DPCD_REV to LANE0_1_STATUS"

[Imre Deak]

This reverts commit 65e46aeaf84aa88539bcff6b8077e05fbd0700da.

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-...@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Cc: Sasha Levin <sas...@kernel.org>
Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14558
Signed-off-by: Imre Deak <imre.d...@intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c 
b/drivers/gpu/drm/display/drm_dp_helper.c
index 772d8e662278..851f0baf9460 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -663,7 +663,7 @@ ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned 
int offset,
         * monitor doesn't power down exactly after the throw away read.
         */
        if (!aux->is_remote) {
-               ret = drm_dp_dpcd_probe(aux, DP_LANE0_1_STATUS);
+               ret = drm_dp_dpcd_probe(aux, DP_DPCD_REV);
                if (ret < 0)
                        return ret;
        }
-- 
2.49.1