[PATCH 6.8 147/158] drm/vmwgfx: Fix crtcs atomic check conditional

Greg Kroah-Hartman
2024-04-23T21:42:40Z

From: Zack Rusin <zack.rusin@broadcom.com>

commit a60ccade88f926e871a57176e86a34bbf0db0098 upstream.

The conditional was supposed to prevent enabling of a crtc state
without a set primary plane. Accidently it also prevented disabling
crtc state with a set primary plane. Neither is correct.

Fix the conditional and just driver-warn when a crtc state has been
enabled without a primary plane which will help debug broken userspace.

Fixes IGT's kms_atomic_interruptible and kms_atomic_transition tests.

Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Fixes: 06ec41909e31 ("drm/vmwgfx: Add and connect CRTC helper functions")
Cc: Broadcom internal kernel review list <bcm-kernel-feedback-list@broadcom.com>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v4.12+
Reviewed-by: Ian Forbes <ian.forbes@broadcom.com>
Reviewed-by: Martin Krastev <martin.krastev@broadcom.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240412025511.78553-5-zack.rusin@broadcom.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -932,6 +932,7 @@ int vmw_du_cursor_plane_atomic_check(str
int vmw_du_crtc_atomic_check(struct drm_crtc *crtc,
struct drm_atomic_state *state)
{
+ struct vmw_private *vmw = vmw_priv(crtc->dev);
struct drm_crtc_state *new_state = drm_atomic_get_new_crtc_state(state,
crtc);
struct vmw_display_unit *du = vmw_crtc_to_du(new_state->crtc);
@@ -939,9 +940,13 @@ int vmw_du_crtc_atomic_check(struct drm_
bool has_primary = new_state->plane_mask &
drm_plane_mask(crtc->primary);

- /* We always want to have an active plane with an active CRTC */
- if (has_primary != new_state->enable)
- return -EINVAL;
+ /*
+ * This is fine in general, but broken userspace might expect
+ * some actual rendering so give a clue as why it's blank.
+ */
+ if (new_state->enable && !has_primary)
+ drm_dbg_driver(&vmw->drm,
+ "CRTC without a primary plane will be blank.\n");

if (new_state->connector_mask != connector_mask &&