Hi Maxime
Am 31.08.26 um 17:34 schrieb Maxime Ripard:
The CRTC reset hook conflates initial software state allocation with
hardware reset. The atomic_create_state hook addresses the software
state side, but drivers may still need to reset hardware to a known good
state during drm_mode_config_reset(), for example during suspend/resume.
Separating hardware reset from state allocation is also useful for the
pending atomic state readout and userspace atomic reset flag series,
which need to create pristine software state without affecting the
hardware.
Introduce a hw_reset hook in struct drm_crtc_helper_funcs that only
resets the hardware, without touching the software state at all. Call it
from drm_mode_config_crtc_reset_with_create_state() after the state has
been successfully created.
Signed-off-by: Maxime Ripard <[email protected]>
Reviewed-by: Thomas Zimmermann <[email protected]>
with comments below.
---
drivers/gpu/drm/drm_mode_config.c | 13 ++++++++++++-
include/drm/drm_modeset_helper_vtables.h | 14 ++++++++++++++
2 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_mode_config.c
b/drivers/gpu/drm/drm_mode_config.c
index 366f6d821242..bb2efc274323 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -28,10 +28,11 @@
#include <drm/drm_encoder.h>
#include <drm/drm_file.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_managed.h>
#include <drm/drm_mode_config.h>
+#include <drm/drm_modeset_helper_vtables.h>
#include <drm/drm_print.h>
#include <drm/drm_colorop.h>
#include <linux/dma-resv.h>
#include "drm_crtc_internal.h"
@@ -228,16 +229,26 @@ static int drm_mode_config_crtc_create_state(struct
drm_crtc *crtc)
return 0;
}
static int drm_mode_config_crtc_reset_with_create_state(struct drm_crtc *crtc)
{
+ const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
Please see the Sahsiko comment about this being NULL. And I suggest to
call the variable 'helpers' because 'funcs' sounds like regular
drm_crtc_funcs. But that's really just nitpicking.
Best regards
Thomas
+ int ret;
+
if (crtc->state) {
crtc->funcs->atomic_destroy_state(crtc, crtc->state);
crtc->state = NULL;
}
- return drm_mode_config_crtc_create_state(crtc);
+ ret = drm_mode_config_crtc_create_state(crtc);
+ if (ret)
+ return ret;
+
+ if (crtc_funcs->hw_reset)
+ crtc_funcs->hw_reset(crtc);
+
+ return 0;
}
static int drm_mode_config_connector_create_state(struct drm_connector *connector)
{
struct drm_connector_state *conn_state;
diff --git a/include/drm/drm_modeset_helper_vtables.h
b/include/drm/drm_modeset_helper_vtables.h
index ca6268945c28..4965356a6314 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -279,10 +279,24 @@ struct drm_crtc_helper_funcs {
* drivers still using legacy CRTC helpers, which is different from the
* rules under atomic.
*/
void (*disable)(struct drm_crtc *crtc);
+ /**
+ * @hw_reset:
+ *
+ * Optional hook for CRTC hardware reset.
+ *
+ * Unlike @drm_crtc_funcs.reset, which both resets hardware and
+ * creates new software state, this hook only resets the
+ * hardware to a known good state without touching the software
+ * state at all.
+ *
+ * This hook is called by drm_mode_config_reset().
+ */
+ void (*hw_reset)(struct drm_crtc *crtc);
+
/**
* @atomic_check:
*
* Drivers should check plane-update related CRTC constraints in this
* hook. They can also check mode related limitations but need to be
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, (HRB 36809, AG Nürnberg)
