The mode fix-up function for simple display helpers is equivalent to the
regular pipeline's CRTC mode fix-up function. It's called to adjust the
CRTC's display mode for the encoder. Add this function for DRM fbconv
helpers.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/drm_simple_kms_helper.c | 15 +++++++++
include/drm/drm_simple_kms_helper.h | 43 +++++++++++++++++++++++++
2 files changed, 58 insertions(+)
diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c b/drivers/gpu/drm/drm_simple_kms_helper.c
index 046055719245..acd9b79bf92a 100644
--- a/drivers/gpu/drm/drm_simple_kms_helper.c
+++ b/drivers/gpu/drm/drm_simple_kms_helper.c
@@ -46,6 +46,20 @@ drm_simple_kms_crtc_mode_valid(struct drm_crtc *crtc,
return pipe->funcs->mode_valid(crtc, mode);
}
+static bool
+drm_simple_kms_crtc_mode_fixup(struct drm_crtc *crtc,
+ const struct drm_display_mode *mode,
+ struct drm_display_mode *adjusted_mode)
+{
+ struct drm_simple_display_pipe *pipe;
+
+ pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
+ if (!pipe->funcs || !pipe->funcs->mode_fixup)
+ return true;
+
+ return pipe->funcs->mode_fixup(crtc, mode, adjusted_mode);
+}
+
static int drm_simple_kms_crtc_check(struct drm_crtc *crtc,
struct drm_crtc_state *state)
{
@@ -87,6 +101,7 @@ static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc,
static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
.mode_valid = drm_simple_kms_crtc_mode_valid,
+ .mode_fixup = drm_simple_kms_crtc_mode_fixup,
.atomic_check = drm_simple_kms_crtc_check,
.atomic_enable = drm_simple_kms_crtc_enable,
.atomic_disable = drm_simple_kms_crtc_disable,
diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h
index 4d89cd0a60db..1b975ab67144 100644
--- a/include/drm/drm_simple_kms_helper.h
+++ b/include/drm/drm_simple_kms_helper.h
@@ -52,6 +52,49 @@ struct drm_simple_display_pipe_funcs {
enum drm_mode_status (*mode_valid)(struct drm_crtc *crtc,
const struct drm_display_mode *mode);
+ /**
+ * @mode_fixup:
+ *
+ * This callback is used to validate a mode. The parameter mode is the
+ * display mode that userspace requested, adjusted_mode is the mode the
+ * encoders need to be fed with. Note that this is the inverse semantics
+ * of the meaning for the &drm_encoder and &drm_bridge_funcs.mode_fixup
+ * vfunc. If the CRTC of the simple display pipe cannot support the
+ * requested conversion from mode to adjusted_mode it should reject the
+ * modeset.
+ *
+ * This function is optional.
+ *
+ * NOTE:
+ *
+ * This function is called in the check phase of atomic modesets, which
+ * can be aborted for any reason (including on userspace's request to
+ * just check whether a configuration would be possible). Atomic drivers
+ * MUST NOT touch any persistent state (hardware or software) or data
+ * structures except the passed in adjusted_mode parameter.
+ *
+ * Atomic drivers which need to inspect and adjust more state should
+ * instead use the @atomic_check callback, but note that they're not
+ * perfectly equivalent: @mode_valid is called from
+ * drm_atomic_helper_check_modeset(), but @atomic_check is called from
+ * drm_atomic_helper_check_planes(), because originally it was meant for
+ * plane update checks only.
+ *
+ * Also beware that userspace can request its own custom modes, neither
+ * core nor helpers filter modes to the list of probe modes reported by
+ * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
+ * that modes are filtered consistently put any CRTC constraints and
+ * limits checks into @mode_valid.
+ *
+ * RETURNS:
+ *
+ * True if an acceptable configuration is possible, false if the modeset
+ * operation should be rejected.
+ */
+ bool (*mode_fixup)(struct drm_crtc *crtc,
+ const struct drm_display_mode *mode,
+ struct drm_display_mode *adjusted_mode);
+
/**
* @enable:
*
--
2.23.0
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