Two quirks to make blind atomic save/restore [1] work correctly: - Mark the DPMS property as immutable for atomic clients, since atomic clients cannot change it. - Allow user-space to set content protection to "enabled", interpret it as "desired". [1]: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/3794 Signed-off-by: Simon Ser <contact@xxxxxxxxxxx> --- I don't have the motivation to write IGT tests for this. drivers/gpu/drm/drm_atomic_uapi.c | 5 +++-- drivers/gpu/drm/drm_property.c | 7 +++++++ 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c index c06d0639d552..95363aac7f69 100644 --- a/drivers/gpu/drm/drm_atomic_uapi.c +++ b/drivers/gpu/drm/drm_atomic_uapi.c @@ -741,8 +741,9 @@ static int drm_atomic_connector_set_property(struct drm_connector *connector, state->scaling_mode = val; } else if (property == config->content_protection_property) { if (val == DRM_MODE_CONTENT_PROTECTION_ENABLED) { - drm_dbg_kms(dev, "only drivers can set CP Enabled\n"); - return -EINVAL; + /* Degrade ENABLED to DESIRED so that blind atomic + * save/restore works as intended. */ + val = DRM_MODE_CONTENT_PROTECTION_DESIRED; } state->content_protection = val; } else if (property == config->hdcp_content_type_property) { diff --git a/drivers/gpu/drm/drm_property.c b/drivers/gpu/drm/drm_property.c index dfec479830e4..dde42986f8cb 100644 --- a/drivers/gpu/drm/drm_property.c +++ b/drivers/gpu/drm/drm_property.c @@ -474,7 +474,14 @@ int drm_mode_getproperty_ioctl(struct drm_device *dev, return -ENOENT; strscpy_pad(out_resp->name, property->name, DRM_PROP_NAME_LEN); + out_resp->flags = property->flags; + if (file_priv->atomic && property == dev->mode_config.dpms_property) { + /* Quirk: indicate that the legacy DPMS property is not + * writable from atomic user-space, so that blind atomic + * save/restore works as intended. */ + out_resp->flags |= DRM_MODE_PROP_IMMUTABLE; + } value_count = property->num_values; values_ptr = u64_to_user_ptr(out_resp->values_ptr); -- 2.38.1
