DDB minimum requirement of crtc configuration (cumulative of all the
enabled planes in crtc) may exceed the allocated DDB for crtc/pipe.
This patch make changes to fail the flip/ioctl if minimum requirement
for pipe exceeds the total ddb allocated to the pipe.
Previously it succeeded but making alloc_size a negative value. Which
will make subsequent calculations for plane ddb allocation bogus & may
lead to screen corruption or system hang.
Changes from V1:
- Improve commit message as per Ander's comment
- Remove extra parentheses (Ander)
Signed-off-by: Mahesh Kumar <mahesh1.kumar@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_pm.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 2a4e9d89cd6f..c0f6aeab0390 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3591,6 +3591,7 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *cstate,
int num_active;
unsigned plane_data_rate[I915_MAX_PLANES] = {};
unsigned plane_y_data_rate[I915_MAX_PLANES] = {};
+ uint16_t total_min_blocks = 0;
/* Clear the partitioning for disabled planes. */
memset(ddb->plane[pipe], 0, sizeof(ddb->plane[pipe]));
@@ -3618,10 +3619,18 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *cstate,
*/
for_each_plane_id_on_crtc(intel_crtc, plane_id) {
- alloc_size -= minimum[plane_id];
- alloc_size -= y_minimum[plane_id];
+ total_min_blocks += minimum[plane_id];
+ total_min_blocks += y_minimum[plane_id];
}
+ if (total_min_blocks > alloc_size) {
+ DRM_DEBUG_KMS("Requested display configuration exceeds system DDB limitations");
+ DRM_DEBUG_KMS("minimum required %d/%d\n", total_min_blocks,
+ alloc_size);
+ return -EINVAL;
+ }
+
+ alloc_size -= total_min_blocks;
ddb->plane[pipe][PLANE_CURSOR].start = alloc->end - minimum[PLANE_CURSOR];
ddb->plane[pipe][PLANE_CURSOR].end = alloc->end;
--
2.11.0
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