Re: [PATCH 2/2] drm/probe_helper: Add drm_helper_probe_single_connector_modes_with_rpm()

On Wed, Jul 18, 2018 at 04:56:40PM -0400, Lyude Paul wrote:

For nouveau, while the GPU is guaranteed to be on when a hotplug has been received, the same assertion does not hold true if a connector probe has been started by userspace without having had received a sysfs event.

So ensure that any connector probing keeps the GPU alive for the duration of the probe by introducing drm_helper_probe_single_connector_modes_with_rpm(). It's the same as drm_helper_probe_single_connector_modes, but it handles holding a power reference to the device for the duration of the connector probe.

Hm, a runtime PM ref is already acquired in nouveau_connector_detect(). I'm wondering why that's not sufficient?

Thanks,

Lukas

Signed-off-by: Lyude Paul lyude@redhat.com Reviewed-by: Karol Herbst karolherbst@gmail.com Cc: Lukas Wunner lukas@wunner.de Cc: stable@vger.kernel.org

---

Changes since v1:

• Add a generic helper to DRM to handle this

drivers/gpu/drm/drm_probe_helper.c | 31 +++++++++++++++++++++ drivers/gpu/drm/nouveau/dispnv50/disp.c | 2 +- drivers/gpu/drm/nouveau/nouveau_connector.c | 4 +-- include/drm/drm_crtc_helper.h | 7 +++-- 4 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c index 527743394150..0a9d6748b854 100644 --- a/drivers/gpu/drm/drm_probe_helper.c +++ b/drivers/gpu/drm/drm_probe_helper.c @@ -31,6 +31,7 @@

#include <linux/export.h> #include <linux/moduleparam.h> +#include <linux/pm_runtime.h>

#include <drm/drmP.h> #include <drm/drm_crtc.h> @@ -541,6 +542,36 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector, } EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);

+/**

• • drm_helper_probe_single_connector_modes_with_rpm - get complete set of

• •                                                display modes
    

• • @connector: connector to probe
• • @maxX: max width for modes
• • @maxY: max height for modes
• • Same as drm_helper_probe_single_connector_modes, except that it makes sure
• • that the device is active by synchronously grabbing a runtime power
• • reference while probing.
• • Returns:
• • The number of modes found on @connector.
• */

+int drm_helper_probe_single_connector_modes_with_rpm(struct drm_connector *connector,

• 				     uint32_t maxX, uint32_t maxY)
  

+{

• int ret;
• ret = pm_runtime_get_sync(connector->dev->dev);
• if (ret < 0 && ret != -EACCES)

• return ret;
  

• ret = drm_helper_probe_single_connector_modes(connector, maxX, maxY);
• pm_runtime_put(connector->dev->dev);
• return ret;

+} +EXPORT_SYMBOL(drm_helper_probe_single_connector_modes_with_rpm);

/**

• drm_kms_helper_hotplug_event - fire off KMS hotplug events
• @dev: drm_device whose connector state changed

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c index fa3ab618a0f9..c54767b50fd8 100644 --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c @@ -858,7 +858,7 @@ static const struct drm_connector_funcs nv50_mstc = { .reset = nouveau_conn_reset, .detect = nv50_mstc_detect,

• .fill_modes = drm_helper_probe_single_connector_modes,

• .fill_modes = drm_helper_probe_single_connector_modes_with_rpm, .destroy = nv50_mstc_destroy, .atomic_duplicate_state = nouveau_conn_atomic_duplicate_state, .atomic_destroy_state = nouveau_conn_atomic_destroy_state,

diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c index 2a45b4c2ceb0..8d9070779261 100644 --- a/drivers/gpu/drm/nouveau/nouveau_connector.c +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c @@ -1088,7 +1088,7 @@ nouveau_connector_funcs = { .reset = nouveau_conn_reset, .detect = nouveau_connector_detect, .force = nouveau_connector_force,

• .fill_modes = drm_helper_probe_single_connector_modes,

• .fill_modes = drm_helper_probe_single_connector_modes_with_rpm, .set_property = nouveau_connector_set_property, .destroy = nouveau_connector_destroy, .atomic_duplicate_state = nouveau_conn_atomic_duplicate_state,

@@ -1103,7 +1103,7 @@ nouveau_connector_funcs_lvds = { .reset = nouveau_conn_reset, .detect = nouveau_connector_detect_lvds, .force = nouveau_connector_force,

• .fill_modes = drm_helper_probe_single_connector_modes,

• .fill_modes = drm_helper_probe_single_connector_modes_with_rpm, .set_property = nouveau_connector_set_property, .destroy = nouveau_connector_destroy, .atomic_duplicate_state = nouveau_conn_atomic_duplicate_state,

diff --git a/include/drm/drm_crtc_helper.h b/include/drm/drm_crtc_helper.h index 6914633037a5..8f3f6d6fcc8c 100644 --- a/include/drm/drm_crtc_helper.h +++ b/include/drm/drm_crtc_helper.h @@ -64,9 +64,10 @@ int drm_helper_crtc_mode_set_base(struct drm_crtc *crtc, int x, int y, struct drm_framebuffer *old_fb);

/* drm_probe_helper.c */ -int drm_helper_probe_single_connector_modes(struct drm_connector

• 			    *connector, uint32_t maxX,
  

• 			    uint32_t maxY);
  

+int drm_helper_probe_single_connector_modes(struct drm_connector *connector,

• 			    uint32_t maxX, uint32_t maxY);
  

+int drm_helper_probe_single_connector_modes_with_rpm(struct drm_connector *connector,

• 				     uint32_t maxX, uint32_t maxY);
  

int drm_helper_probe_detect(struct drm_connector *connector, struct drm_modeset_acquire_ctx *ctx, bool force); -- 2.17.1