[PATCH 03/14] drm/amd/display: Lock DC and exit IPS when changing backlight

[Hamza Mahfooz]

From: Leo Li <sunpeng...@amd.com>

Backlight updates require aux and/or register access. Therefore, driver
needs to disallow IPS beforehand.

So, acquire the dc lock before calling into dc to update backlight - we
should be doing this regardless of IPS. Then, while the lock is held,
disallow IPS before calling into dc, then allow IPS afterwards (if it
was previously allowed).

Cc: sta...@vger.kernel.org # 6.10+
Reviewed-by: Aurabindo Pillai <aurabindo.pil...@amd.com>
Reviewed-by: Roman Li <roman...@amd.com>
Signed-off-by: Leo Li <sunpeng...@amd.com>
Signed-off-by: Hamza Mahfooz <hamza.mahf...@amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c 
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 351f8b0fe7a1..fa26b8d59f23 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4512,7 +4512,7 @@ static void amdgpu_dm_backlight_set_level(struct 
amdgpu_display_manager *dm,
        struct amdgpu_dm_backlight_caps caps;
        struct dc_link *link;
        u32 brightness;
-       bool rc;
+       bool rc, reallow_idle = false;
 
        amdgpu_dm_update_backlight_caps(dm, bl_idx);
        caps = dm->backlight_caps[bl_idx];
@@ -4525,6 +4525,12 @@ static void amdgpu_dm_backlight_set_level(struct 
amdgpu_display_manager *dm,
        link = (struct dc_link *)dm->backlight_link[bl_idx];
 
        /* Change brightness based on AUX property */
+       mutex_lock(&dm->dc_lock);
+       if (dm->dc->caps.ips_support && dm->dc->ctx->dmub_srv->idle_allowed) {
+               dc_allow_idle_optimizations(dm->dc, false);
+               reallow_idle = true;
+       }
+
        if (caps.aux_support) {
                rc = dc_link_set_backlight_level_nits(link, true, brightness,
                                                      
AUX_BL_DEFAULT_TRANSITION_TIME_MS);
@@ -4536,6 +4542,11 @@ static void amdgpu_dm_backlight_set_level(struct 
amdgpu_display_manager *dm,
                        DRM_DEBUG("DM: Failed to update backlight on 
eDP[%d]\n", bl_idx);
        }
 
+       if (dm->dc->caps.ips_support && reallow_idle)
+               dc_allow_idle_optimizations(dm->dc, true);
+
+       mutex_unlock(&dm->dc_lock);
+
        if (rc)
                dm->actual_brightness[bl_idx] = user_brightness;
 }
-- 
2.46.0