From 8f86c82aba8b13e732cfdd6d0e19a7dd48197e43 Mon Sep 17 00:00:00 2001 From: Simon Ser Date: Fri, 2 Apr 2021 13:22:12 +0200 Subject: [PATCH] drm/connector: demote connector force-probes for non-master clients Force-probing a connector can be slow and cause flickering. As this affects the global KMS state, let's make it so only the DRM master can force-probe a connector. Non-master DRM clients won't be able to force-probe a connector anymore. Instead, KMS will perform a regular read-only connector query. Signed-off-by: Simon Ser Acked-by: Pekka Paalanen Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210402112212.5625-1-contact@emersion.fr --- drivers/gpu/drm/drm_connector.c | 11 ++++++++--- include/uapi/drm/drm_mode.h | 7 ++++--- 2 files changed, 12 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index eab8c0b82de2..9de145351546 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -20,6 +20,7 @@ * OF THIS SOFTWARE. */ +#include #include #include #include @@ -2376,9 +2377,13 @@ int drm_mode_getconnector(struct drm_device *dev, void *data, mutex_lock(&dev->mode_config.mutex); if (out_resp->count_modes == 0) { - connector->funcs->fill_modes(connector, - dev->mode_config.max_width, - dev->mode_config.max_height); + if (drm_is_current_master(file_priv)) + connector->funcs->fill_modes(connector, + dev->mode_config.max_width, + dev->mode_config.max_height); + else + drm_dbg_kms(dev, "User-space requested a forced probe on [CONNECTOR:%d:%s] but is not the DRM master, demoting to read-only probe", + connector->base.id, connector->name); } out_resp->mm_width = connector->display_info.width_mm; diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h index a5e76aa06ad5..9b6722d45f36 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/drm/drm_mode.h @@ -413,9 +413,10 @@ enum drm_mode_subconnector { * * **Force-probing a connector** * - * If the @count_modes field is set to zero, the kernel will perform a forced - * probe on the connector to refresh the connector status, modes and EDID. - * A forced-probe can be slow, might cause flickering and the ioctl will block. + * If the @count_modes field is set to zero and the DRM client is the current + * DRM master, the kernel will perform a forced probe on the connector to + * refresh the connector status, modes and EDID. A forced-probe can be slow, + * might cause flickering and the ioctl will block. * * User-space needs to force-probe connectors to ensure their metadata is * up-to-date at startup and after receiving a hot-plug event. User-space -- 2.11.0