diff options
| -rw-r--r-- | Documentation/gpu/todo.rst | 21 | ||||
| -rw-r--r-- | drivers/gpu/drm/tiny/gm12u320.c | 44 | ||||
| -rw-r--r-- | drivers/gpu/drm/udl/udl_drv.c | 17 | ||||
| -rw-r--r-- | drivers/gpu/drm/udl/udl_drv.h | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/udl/udl_main.c | 10 | ||||
| -rw-r--r-- | drivers/usb/core/usb.c | 32 | ||||
| -rw-r--r-- | include/linux/usb.h | 2 |
7 files changed, 119 insertions, 8 deletions
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index 40ccac61137e..22ce801e3a8d 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -613,6 +613,27 @@ Some of these date from the very introduction of KMS in 2008 ... Level: Intermediate +Remove automatic page mapping from dma-buf importing +---------------------------------------------------- + +When importing dma-bufs, the dma-buf and PRIME frameworks automatically map +imported pages into the importer's DMA area. drm_gem_prime_fd_to_handle() and +drm_gem_prime_handle_to_fd() require that importers call dma_buf_attach() +even if they never do actual device DMA, but only CPU access through +dma_buf_vmap(). This is a problem for USB devices, which do not support DMA +operations. + +To fix the issue, automatic page mappings should be removed from the +buffer-sharing code. Fixing this is a bit more involved, since the import/export +cache is also tied to &drm_gem_object.import_attach. Meanwhile we paper over +this problem for USB devices by fishing out the USB host controller device, as +long as that supports DMA. Otherwise importing can still needlessly fail. + +Contact: Thomas Zimmermann <tzimmermann@suse.de>, Daniel Vetter + +Level: Advanced + + Better Testing ============== diff --git a/drivers/gpu/drm/tiny/gm12u320.c b/drivers/gpu/drm/tiny/gm12u320.c index 33f65f4626e5..23866a54e3f9 100644 --- a/drivers/gpu/drm/tiny/gm12u320.c +++ b/drivers/gpu/drm/tiny/gm12u320.c @@ -83,6 +83,7 @@ MODULE_PARM_DESC(eco_mode, "Turn on Eco mode (less bright, more silent)"); struct gm12u320_device { struct drm_device dev; + struct device *dmadev; struct drm_simple_display_pipe pipe; struct drm_connector conn; unsigned char *cmd_buf; @@ -601,6 +602,22 @@ static const uint64_t gm12u320_pipe_modifiers[] = { DRM_FORMAT_MOD_INVALID }; +/* + * FIXME: Dma-buf sharing requires DMA support by the importing device. + * This function is a workaround to make USB devices work as well. + * See todo.rst for how to fix the issue in the dma-buf framework. + */ +static struct drm_gem_object *gm12u320_gem_prime_import(struct drm_device *dev, + struct dma_buf *dma_buf) +{ + struct gm12u320_device *gm12u320 = to_gm12u320(dev); + + if (!gm12u320->dmadev) + return ERR_PTR(-ENODEV); + + return drm_gem_prime_import_dev(dev, dma_buf, gm12u320->dmadev); +} + DEFINE_DRM_GEM_FOPS(gm12u320_fops); static const struct drm_driver gm12u320_drm_driver = { @@ -614,6 +631,7 @@ static const struct drm_driver gm12u320_drm_driver = { .fops = &gm12u320_fops, DRM_GEM_SHMEM_DRIVER_OPS, + .gem_prime_import = gm12u320_gem_prime_import, }; static const struct drm_mode_config_funcs gm12u320_mode_config_funcs = { @@ -640,15 +658,18 @@ static int gm12u320_usb_probe(struct usb_interface *interface, struct gm12u320_device, dev); if (IS_ERR(gm12u320)) return PTR_ERR(gm12u320); + dev = &gm12u320->dev; + + gm12u320->dmadev = usb_intf_get_dma_device(to_usb_interface(dev->dev)); + if (!gm12u320->dmadev) + drm_warn(dev, "buffer sharing not supported"); /* not an error */ INIT_DELAYED_WORK(&gm12u320->fb_update.work, gm12u320_fb_update_work); mutex_init(&gm12u320->fb_update.lock); - dev = &gm12u320->dev; - ret = drmm_mode_config_init(dev); if (ret) - return ret; + goto err_put_device; dev->mode_config.min_width = GM12U320_USER_WIDTH; dev->mode_config.max_width = GM12U320_USER_WIDTH; @@ -658,15 +679,15 @@ static int gm12u320_usb_probe(struct usb_interface *interface, ret = gm12u320_usb_alloc(gm12u320); if (ret) - return ret; + goto err_put_device; ret = gm12u320_set_ecomode(gm12u320); if (ret) - return ret; + goto err_put_device; ret = gm12u320_conn_init(gm12u320); if (ret) - return ret; + goto err_put_device; ret = drm_simple_display_pipe_init(&gm12u320->dev, &gm12u320->pipe, @@ -676,24 +697,31 @@ static int gm12u320_usb_probe(struct usb_interface *interface, gm12u320_pipe_modifiers, &gm12u320->conn); if (ret) - return ret; + goto err_put_device; drm_mode_config_reset(dev); usb_set_intfdata(interface, dev); ret = drm_dev_register(dev, 0); if (ret) - return ret; + goto err_put_device; drm_fbdev_generic_setup(dev, 0); return 0; + +err_put_device: + put_device(gm12u320->dmadev); + return ret; } static void gm12u320_usb_disconnect(struct usb_interface *interface) { struct drm_device *dev = usb_get_intfdata(interface); + struct gm12u320_device *gm12u320 = to_gm12u320(dev); + put_device(gm12u320->dmadev); + gm12u320->dmadev = NULL; drm_dev_unplug(dev); drm_atomic_helper_shutdown(dev); } diff --git a/drivers/gpu/drm/udl/udl_drv.c b/drivers/gpu/drm/udl/udl_drv.c index 9269092697d8..5703277c6f52 100644 --- a/drivers/gpu/drm/udl/udl_drv.c +++ b/drivers/gpu/drm/udl/udl_drv.c @@ -32,6 +32,22 @@ static int udl_usb_resume(struct usb_interface *interface) return drm_mode_config_helper_resume(dev); } +/* + * FIXME: Dma-buf sharing requires DMA support by the importing device. + * This function is a workaround to make USB devices work as well. + * See todo.rst for how to fix the issue in the dma-buf framework. + */ +static struct drm_gem_object *udl_driver_gem_prime_import(struct drm_device *dev, + struct dma_buf *dma_buf) +{ + struct udl_device *udl = to_udl(dev); + + if (!udl->dmadev) + return ERR_PTR(-ENODEV); + + return drm_gem_prime_import_dev(dev, dma_buf, udl->dmadev); +} + DEFINE_DRM_GEM_FOPS(udl_driver_fops); static const struct drm_driver driver = { @@ -40,6 +56,7 @@ static const struct drm_driver driver = { /* GEM hooks */ .fops = &udl_driver_fops, DRM_GEM_SHMEM_DRIVER_OPS, + .gem_prime_import = udl_driver_gem_prime_import, .name = DRIVER_NAME, .desc = DRIVER_DESC, diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h index 875e73551ae9..cc16a13316e4 100644 --- a/drivers/gpu/drm/udl/udl_drv.h +++ b/drivers/gpu/drm/udl/udl_drv.h @@ -50,6 +50,7 @@ struct urb_list { struct udl_device { struct drm_device drm; struct device *dev; + struct device *dmadev; struct drm_simple_display_pipe display_pipe; diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c index 0e2a376cb075..853f147036f6 100644 --- a/drivers/gpu/drm/udl/udl_main.c +++ b/drivers/gpu/drm/udl/udl_main.c @@ -315,6 +315,10 @@ int udl_init(struct udl_device *udl) DRM_DEBUG("\n"); + udl->dmadev = usb_intf_get_dma_device(to_usb_interface(dev->dev)); + if (!udl->dmadev) + drm_warn(dev, "buffer sharing not supported"); /* not an error */ + mutex_init(&udl->gem_lock); if (!udl_parse_vendor_descriptor(udl)) { @@ -343,12 +347,18 @@ int udl_init(struct udl_device *udl) err: if (udl->urbs.count) udl_free_urb_list(dev); + put_device(udl->dmadev); DRM_ERROR("%d\n", ret); return ret; } int udl_drop_usb(struct drm_device *dev) { + struct udl_device *udl = to_udl(dev); + udl_free_urb_list(dev); + put_device(udl->dmadev); + udl->dmadev = NULL; + return 0; } diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index 8f07b0516100..a566bb494e24 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -748,6 +748,38 @@ void usb_put_intf(struct usb_interface *intf) } EXPORT_SYMBOL_GPL(usb_put_intf); +/** + * usb_intf_get_dma_device - acquire a reference on the usb interface's DMA endpoint + * @intf: the usb interface + * + * While a USB device cannot perform DMA operations by itself, many USB + * controllers can. A call to usb_intf_get_dma_device() returns the DMA endpoint + * for the given USB interface, if any. The returned device structure must be + * released with put_device(). + * + * See also usb_get_dma_device(). + * + * Returns: A reference to the usb interface's DMA endpoint; or NULL if none + * exists. + */ +struct device *usb_intf_get_dma_device(struct usb_interface *intf) +{ + struct usb_device *udev = interface_to_usbdev(intf); + struct device *dmadev; + + if (!udev->bus) + return NULL; + + dmadev = get_device(udev->bus->sysdev); + if (!dmadev || !dmadev->dma_mask) { + put_device(dmadev); + return NULL; + } + + return dmadev; +} +EXPORT_SYMBOL_GPL(usb_intf_get_dma_device); + /* USB device locking * * USB devices and interfaces are locked using the semaphore in their diff --git a/include/linux/usb.h b/include/linux/usb.h index 7d72c4e0713c..d6a41841b93e 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -746,6 +746,8 @@ extern int usb_lock_device_for_reset(struct usb_device *udev, extern int usb_reset_device(struct usb_device *dev); extern void usb_queue_reset_device(struct usb_interface *dev); +extern struct device *usb_intf_get_dma_device(struct usb_interface *intf); + #ifdef CONFIG_ACPI extern int usb_acpi_set_power_state(struct usb_device *hdev, int index, bool enable); |