Add the case to reserve multiple pairs mixers for high resolution.
Current code only supports one pair of mixer usage case. To support
quad-pipe usage case, two pairs of mixers are needed.

Current code resets number of mixer on failure of pair's peer test and
retry on another pair. If two pairs are needed, the failure on the test
of 2nd pair results clearing to the 1st pair. This patch only clear the
bit for the 2nd pair allocation before retry on another pair.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
index 2b03ab907c2bc..5c9bb64df7930 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c
@@ -306,7 +306,11 @@ static int _dpu_rm_reserve_lms(struct dpu_rm *rm,
 		if (!rm->mixer_blks[i])
 			continue;
 
-		lm_count = 0;
+		/*
+		 * Clear the last bit to drop the previous primary mixer if
+		 * fail to find its peer.
+		 */
+		lm_count &= 0xfe;
 		lm_idx[lm_count] = i;
 
 		if (!_dpu_rm_check_lm_and_get_connected_blks(rm, global_state,

-- 
2.34.1