[PATCH v3 3/4] drm/atomic: Return user readable error in atomic_ioctl
Arun R Murthy
arun.r.murthy at intel.com
Fri Aug 22 07:00:03 UTC 2025
Add user readable error codes for failure cases in drm_atomic_ioctl() so
that user can decode the error code and take corrective measurements.
Signed-off-by: Arun R Murthy <arun.r.murthy at intel.com>
---
drivers/gpu/drm/drm_atomic.c | 6 ++++
drivers/gpu/drm/drm_atomic_uapi.c | 60 ++++++++++++++++++++++++++++++++-------
2 files changed, 56 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index cd15cf52f0c9144711da5879da57884674aea9e4..5f25e6d3cf6cf246f83a8c39450b410e97fe45bb 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -1513,6 +1513,9 @@ int drm_atomic_check_only(struct drm_atomic_state *state)
if (drm_atomic_crtc_needs_modeset(new_crtc_state)) {
drm_dbg_atomic(dev, "[CRTC:%d:%s] requires full modeset\n",
crtc->base.id, crtc->name);
+ state->error_code->failure_flags =
+ DRM_MODE_ATOMIC_CRTC_NEED_FULL_MODESET;
+
return -EINVAL;
}
}
@@ -1537,8 +1540,11 @@ int drm_atomic_check_only(struct drm_atomic_state *state)
drm_dbg_atomic(dev,
"driver added CRTC to commit: requested 0x%x, affected 0x%0x\n",
requested_crtc, affected_crtc);
+ state->error_code->failure_flags = DRM_MODE_ATOMIC_NEED_FULL_MODESET;
WARN(!state->allow_modeset, "adding CRTC not allowed without modesets: requested 0x%x, affected 0x%0x\n",
requested_crtc, affected_crtc);
+
+ return -EINVAL;
}
return 0;
diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index ecc73d52bfae41a7ef455a7e13649ec56c690b90..94eaf9c98eb4ac2455799f1416010d366e1b5bbc 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -1058,6 +1058,9 @@ int drm_atomic_set_property(struct drm_atomic_state *state,
ret = drm_atomic_crtc_get_property(crtc, crtc_state,
prop, &old_val);
ret = drm_atomic_check_prop_changes(ret, old_val, prop_value, prop);
+ if (ret)
+ state->error_code->failure_flags =
+ DRM_MODE_ATOMIC_ASYNC_PROP_CHANGED;
break;
}
@@ -1089,6 +1092,8 @@ int drm_atomic_set_property(struct drm_atomic_state *state,
/* ask the driver if this non-primary plane is supported */
if (plane->type != DRM_PLANE_TYPE_PRIMARY) {
+ state->error_code->failure_flags =
+ DRM_MODE_ATOMIC_ASYNC_NOT_SUP_PLANE;
ret = -EINVAL;
if (plane_funcs && plane_funcs->atomic_async_check)
@@ -1380,6 +1385,13 @@ set_async_flip(struct drm_atomic_state *state)
}
}
+#define FAILURE_REASON(flag, reason) #reason,
+const char *drm_mode_atomic_failure_string[] = {
+ DRM_MODE_ATOMIC_FAILURE_REASON
+};
+
+#undef FAILURE_REASON
+
int drm_mode_atomic_ioctl(struct drm_device *dev,
void *data, struct drm_file *file_priv)
{
@@ -1389,9 +1401,11 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
uint32_t __user *props_ptr = (uint32_t __user *)(unsigned long)(arg->props_ptr);
uint64_t __user *prop_values_ptr = (uint64_t __user *)(unsigned long)(arg->prop_values_ptr);
unsigned int copied_objs, copied_props;
- struct drm_atomic_state *state;
+ struct drm_atomic_state *state = NULL;
struct drm_modeset_acquire_ctx ctx;
struct drm_out_fence_state *fence_state;
+ struct drm_mode_atomic_err_code error_code;
+ struct drm_mode_atomic_err_code __user *error_code_ptr;
int ret = 0;
unsigned int i, j, num_fences;
bool async_flip = false;
@@ -1400,6 +1414,11 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
return -EOPNOTSUPP;
+ if (!arg->reserved)
+ drm_err(dev, "memory not allocated for drm_atomic error reporting\n");
+
+ memset(&error_code, 0, sizeof(struct drm_mode_atomic_err_code));
+
/* disallow for userspace that has not enabled atomic cap (even
* though this may be a bit overkill, since legacy userspace
* wouldn't know how to call this ioctl)
@@ -1407,24 +1426,25 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
if (!file_priv->atomic) {
drm_dbg_atomic(dev,
"commit failed: atomic cap not enabled\n");
- return -EINVAL;
+ error_code.failure_flags = DRM_MODE_ATOMIC_CAP_NOT_ENABLED;
+ ret = -EINVAL;
+ goto out;
}
if (arg->flags & ~DRM_MODE_ATOMIC_FLAGS) {
drm_dbg_atomic(dev, "commit failed: invalid flag\n");
- return -EINVAL;
- }
-
- if (arg->reserved) {
- drm_dbg_atomic(dev, "commit failed: reserved field set\n");
- return -EINVAL;
+ error_code.failure_flags = DRM_MODE_ATOMIC_INVALID_FLAG;
+ ret = -EINVAL;
+ goto out;
}
if (arg->flags & DRM_MODE_PAGE_FLIP_ASYNC) {
if (!dev->mode_config.async_page_flip) {
drm_dbg_atomic(dev,
"commit failed: DRM_MODE_PAGE_FLIP_ASYNC not supported\n");
- return -EINVAL;
+ error_code.failure_flags = DRM_MODE_ATOMIC_PAGE_FLIP_ASYNC;
+ ret = -EINVAL;
+ goto out;
}
async_flip = true;
@@ -1435,7 +1455,9 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
(arg->flags & DRM_MODE_PAGE_FLIP_EVENT)) {
drm_dbg_atomic(dev,
"commit failed: page-flip event requested with test-only commit\n");
- return -EINVAL;
+ error_code.failure_flags = DRM_MODE_ATOMIC_FLIP_EVENT_WITH_CHECKONLY;
+ ret = -EINVAL;
+ goto out;
}
state = drm_atomic_state_alloc(dev);
@@ -1446,6 +1468,8 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
state->acquire_ctx = &ctx;
state->allow_modeset = !!(arg->flags & DRM_MODE_ATOMIC_ALLOW_MODESET);
+ state->error_code = &error_code;
+
retry:
copied_objs = 0;
copied_props = 0;
@@ -1542,6 +1566,22 @@ int drm_mode_atomic_ioctl(struct drm_device *dev,
}
out:
+ /* update the error code if any error to allow user handling it */
+ if (ret < 0 && arg->reserved) {
+ error_code_ptr = (struct drm_mode_atomic_err_code __user *)
+ (unsigned long)arg->reserved;
+
+ strscpy_pad(error_code.failure_string,
+ drm_mode_atomic_failure_string[error_code.failure_flags],
+ sizeof(error_code.failure_string));
+
+ if (copy_to_user(error_code_ptr, &error_code, sizeof(error_code)))
+ return -EFAULT;
+ }
+
+ if (!state)
+ return ret;
+
complete_signaling(dev, state, fence_state, num_fences, !ret);
if (ret == -EDEADLK) {
--
2.25.1
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