Re: [PATCH 2/4 v3] drm: Introduce drm_connector_register_all() helper

Hi

On Wed, Mar 23, 2016 at 9:42 AM, Alexey Brodkin Alexey.Brodkin@synopsys.com wrote:

As a pair to already existing drm_connector_unregister_all() we're adding generic implementation of what is already done in some drivers.

Once this helper is implemented we'll be ready to switch existing driver-specific implementations with the generic one.

Signed-off-by: Alexey Brodkin abrodkin@synopsys.com Cc: Daniel Vetter daniel@ffwll.ch Cc: David Airlie airlied@linux.ie

---

Changes v2 -> v3:

• Updated title with capital after colon
• Simplified failure path with direct and unconditional invocation of unregister_all()
• Updated kerneldoc description of the drm_connector_register_all()

Changes v1 -> v2:

• Rename drm_connector_unplug_all() to drm_connector_unregister_all()
• Use drm_for_each_connector() instead of list_for_each_entry()
• Updated kerneldoc for drm_dev_register()

drivers/gpu/drm/drm_crtc.c | 43 +++++++++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/drm_drv.c | 6 +++++- include/drm/drm_crtc.h | 3 ++- 3 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index 65488a6..21eea11 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -1081,6 +1081,49 @@ void drm_connector_unregister(struct drm_connector *connector) EXPORT_SYMBOL(drm_connector_unregister);

/**

• • drm_connector_register_all - register all connectors
• • @dev: drm device
• • This function registers all connectors in sysfs and other places so that
• • userspace can start to access them. Drivers can call it after calling
• • drm_dev_register() to complete the device registration, if they don't call
• • drm_connector_register() on each connector individually.
• • When a device is unplugged and should be removed from userspace access,
• • call drm_connector_unregister_all(), which is the inverse of this
• • function.
• • Returns:
• • Zero on success, error code on failure.
• */

+int drm_connector_register_all(struct drm_device *dev) +{

•   struct drm_connector *connector;
  

•   int ret;
  

•   mutex_lock(&dev->mode_config.mutex);
  

•   drm_for_each_connector(connector, dev) {
  

•           ret = drm_connector_register(connector);
  

•           if (ret) {
  

•                   /*
  

•                    * We may safely call unregister_all() here within
  

•                    * area locked with mutex because unregister_all()
  

•                    * doesn't use locks inside (see a comment in that
  

•                    * function).
  

•                    */
  

Ugh? unregister_all() says:

/* FIXME: taking the mode config mutex ends up in a clash with sysfs */

This strongly contradicts your comment. Anyway, regardless how you want to fix it: You better unlock the mode-config mutex before returning below.

Thanks David

•                   drm_connector_unregister_all(dev);
  

•                   return ret;
  

•           }
  

•   }
  

•   mutex_unlock(&dev->mode_config.mutex);
  

•   return 0;
  

+} +EXPORT_SYMBOL(drm_connector_register_all);

+/**

• drm_connector_unregister_all - unregister connector userspace interfaces
• @dev: drm device

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 167c8d3..2c9a2b6 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -715,7 +715,11 @@ EXPORT_SYMBOL(drm_dev_unref);

• Register the DRM device @dev with the system, advertise device to user-space
• and start normal device operation. @dev must be allocated via drm_dev_alloc()

• • previously.

• • previously. Right after drm_dev_register() the driver should call
• • drm_connector_register_all() to register all connectors in sysfs. This is
• • a separate call for backward compatibility with drivers still using
• • the deprecated ->load() callback, where connectors are registered from within
• • the ->load() callback.
  • Never call this twice on any device!

diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index 42d9f4d..6a34117 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -2214,7 +2214,8 @@ void drm_connector_unregister(struct drm_connector *connector);

extern void drm_connector_cleanup(struct drm_connector *connector); extern unsigned int drm_connector_index(struct drm_connector *connector); -/* helper to unregister all connectors from sysfs for device */ +/* helpers to {un}register all connectors from sysfs for device */ +extern int drm_connector_register_all(struct drm_device *dev); extern void drm_connector_unregister_all(struct drm_device *dev);

extern int drm_bridge_add(struct drm_bridge *bridge);

2.5.0