Hi
On Fri, Feb 12, 2016 at 8:50 PM, Haixia Shi hshi@chromium.org wrote:
v1: Remove the general drm_device_is_unplugged() checks, and move the unplugged flag handling logic into drm/udl. In general we want to keep driver-specific logic out of common drm code.
v2: Based on discussion with Stephane and David, drop most of the unplugged flag handling logic in drm/udl except for udl_detect() and udl_fb_open(). The intention is to treat the device removal as a connector-unplug, and kep the UDL device fully functional.
v3: Based on feedback from David, entirely drop the "unplugged" flag and all related code. There is no need to check for the unplugged flag as the existing udl_usb_disconnect() behavior already ensures the controller is removed, and all code paths that uses the usb-device are not reachable after unplug.
When a UDL monitor is unplugged, we need to still treat it as a fully functional device which just happens to have its connector unplugged. This allows user-space to properly deallocate fbs and dumb buffers before closing the device.
This drops the "unplugged" flag hack, which puts the device in a non-functional state after USB unplug and rejects most operations on the device such as ioctls with error -ENODEV.
Signed-off-by: Haixia Shi hshi@chromium.org Reviewed-by: Stéphane Marchesin marcheu@chromium.org Cc: David Herrmann dh.herrmann@gmail.com Cc: Daniel Vetter daniel@ffwll.ch
drivers/gpu/drm/drm_drv.c | 6 ------ drivers/gpu/drm/drm_fops.c | 2 -- drivers/gpu/drm/drm_gem.c | 3 --- drivers/gpu/drm/drm_ioctl.c | 3 --- drivers/gpu/drm/drm_vm.c | 3 --- drivers/gpu/drm/udl/udl_connector.c | 2 -- drivers/gpu/drm/udl/udl_fb.c | 6 ------ include/drm/drmP.h | 14 -------------- 8 files changed, 39 deletions(-)
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 167c8d3..f93ee12 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -376,9 +376,6 @@ struct drm_minor *drm_minor_acquire(unsigned int minor_id)
if (!minor) { return ERR_PTR(-ENODEV);
} else if (drm_device_is_unplugged(minor->dev)) {drm_dev_unref(minor->dev);return ERR_PTR(-ENODEV); } return minor;@@ -464,9 +461,6 @@ void drm_unplug_dev(struct drm_device *dev) drm_minor_unregister(dev, DRM_MINOR_CONTROL);
mutex_lock(&drm_global_mutex);
drm_device_set_unplugged(dev);if (dev->open_count == 0) { drm_put_dev(dev); }diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c index 1ea8790..b4332d4 100644 --- a/drivers/gpu/drm/drm_fops.c +++ b/drivers/gpu/drm/drm_fops.c @@ -497,8 +497,6 @@ int drm_release(struct inode *inode, struct file *filp)
if (!--dev->open_count) { retcode = drm_lastclose(dev);
if (drm_device_is_unplugged(dev))drm_put_dev(dev);
Who frees the udl device now? What code-path is responsible to call drm_dev_unregister() for udl devices? This hunk looks bogus to me. Please elaborate.
} mutex_unlock(&drm_global_mutex);diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 2e8c77e..c622e32 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -900,9 +900,6 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) struct drm_vma_offset_node *node; int ret;
if (drm_device_is_unplugged(dev))return -ENODEV;drm_vma_offset_lock_lookup(dev->vma_offset_manager); node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager, vma->vm_pgoff,diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 8ce2a0c..f959074 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -695,9 +695,6 @@ long drm_ioctl(struct file *filp,
dev = file_priv->minor->dev;
if (drm_device_is_unplugged(dev))return -ENODEV;is_driver_ioctl = nr >= DRM_COMMAND_BASE && nr < DRM_COMMAND_END; if (is_driver_ioctl) {diff --git a/drivers/gpu/drm/drm_vm.c b/drivers/gpu/drm/drm_vm.c index f90bd5f..3a68be4 100644 --- a/drivers/gpu/drm/drm_vm.c +++ b/drivers/gpu/drm/drm_vm.c @@ -657,9 +657,6 @@ int drm_legacy_mmap(struct file *filp, struct vm_area_struct *vma) struct drm_device *dev = priv->minor->dev; int ret;
if (drm_device_is_unplugged(dev))return -ENODEV;mutex_lock(&dev->struct_mutex); ret = drm_mmap_locked(filp, vma); mutex_unlock(&dev->struct_mutex);diff --git a/drivers/gpu/drm/udl/udl_connector.c b/drivers/gpu/drm/udl/udl_connector.c index 4709b54..a6d5e21 100644 --- a/drivers/gpu/drm/udl/udl_connector.c +++ b/drivers/gpu/drm/udl/udl_connector.c @@ -96,8 +96,6 @@ static int udl_mode_valid(struct drm_connector *connector, static enum drm_connector_status udl_detect(struct drm_connector *connector, bool force) {
if (drm_device_is_unplugged(connector->dev))return connector_status_disconnected; return connector_status_connected;
Who marks a connector as "disconnect" once the device is removed?
}
diff --git a/drivers/gpu/drm/udl/udl_fb.c b/drivers/gpu/drm/udl/udl_fb.c index 200419d..29aca6c 100644 --- a/drivers/gpu/drm/udl/udl_fb.c +++ b/drivers/gpu/drm/udl/udl_fb.c @@ -321,12 +321,6 @@ static void udl_fb_imageblit(struct fb_info *info, const struct fb_image *image) static int udl_fb_open(struct fb_info *info, int user) { struct udl_fbdev *ufbdev = info->par;
struct drm_device *dev = ufbdev->ufb.base.dev;struct udl_device *udl = dev->dev_private;/* If the USB device is gone, we don't accept new opens */if (drm_device_is_unplugged(udl->ddev))return -ENODEV; ufbdev->fb_count++;diff --git a/include/drm/drmP.h b/include/drm/drmP.h index d7162cf..40c6099 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -748,7 +748,6 @@ struct drm_device { struct drm_minor *control; /**< Control node */ struct drm_minor *primary; /**< Primary node */ struct drm_minor *render; /**< Render node */
atomic_t unplugged; /**< Flag whether dev is dead */ struct inode *anon_inode; /**< inode for private address-space */ char *unique; /**< unique name of the device */ /*@} */@@ -879,19 +878,6 @@ static __inline__ int drm_core_check_feature(struct drm_device *dev, return ((dev->driver->driver_features & feature) ? 1 : 0); }
-static inline void drm_device_set_unplugged(struct drm_device *dev) -{
smp_wmb();atomic_set(&dev->unplugged, 1);-}
-static inline int drm_device_is_unplugged(struct drm_device *dev) -{
int ret = atomic_read(&dev->unplugged);smp_rmb();return ret;-}
static inline bool drm_is_render_client(const struct drm_file *file_priv) { return file_priv->minor->type == DRM_MINOR_RENDER;
Did you actually test this patch? How is it supposed to work? Please explain _exactly_ in your commit message what the new semantics are. I highly doubt that this patch does what you want. Also, please run kmemleak on your tests to verify that all memory is actually released.
Generally, I like the approach. However, I think you still need a state that marks a device as dropped. I'd do something like this:
1) In udl_usb_disconnect(), set udl->udev to NULL, locked by mode_config.mutex. This should be the _first_ thing you do there. This serves as barrier against ->get_modes(), which is the only path that uses "udl->udev".
2) In udl_detect(), return 'connector_status_disconnected' if "udl->udev" is NULL.
3) In udl_get_edid() add "if (WARN_ON(!udl->udev)) return NULL;"
4) Hook into f_ops.release() and call into drm_release(). But afterwards you have to call drm_put_dev() if open_count is 0 now.
Thanks David