diff options
| -rw-r--r-- | Documentation/gpu/drm-uapi.rst | 6 | ||||
| -rw-r--r-- | drivers/gpu/drm/armada/armada_drv.c | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/drm_ioctl.c | 58 | ||||
| -rw-r--r-- | drivers/gpu/drm/drm_platform.c | 18 | ||||
| -rw-r--r-- | drivers/gpu/drm/etnaviv/etnaviv_drv.c | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/exynos/exynos_drm_drv.c | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/imx/imx-drm-core.c | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/msm/msm_drv.c | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/nouveau/nouveau_drm.c | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/omapdrm/omap_drv.c | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/shmobile/shmob_drm_drv.c | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/tilcdc/tilcdc_drv.c | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/virtio/virtgpu_drm_bus.c | 10 | ||||
| -rw-r--r-- | drivers/gpu/drm/virtio/virtgpu_drv.c | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/virtio/virtgpu_drv.h | 1 | ||||
| -rw-r--r-- | include/drm/drmP.h | 1 |
17 files changed, 64 insertions, 41 deletions
diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst index 6da1e77e55fa..a1c6f0103bc4 100644 --- a/Documentation/gpu/drm-uapi.rst +++ b/Documentation/gpu/drm-uapi.rst @@ -14,6 +14,12 @@ management, and output management. Cover generic ioctls and sysfs layout here. We only need high-level info, since man pages should cover the rest. +libdrm Device Lookup +==================== + +.. kernel-doc:: drivers/gpu/drm/drm_ioctl.c + :doc: getunique and setversion story + Render nodes ============ diff --git a/drivers/gpu/drm/armada/armada_drv.c b/drivers/gpu/drm/armada/armada_drv.c index cb21c0b6374a..f5ebdd681445 100644 --- a/drivers/gpu/drm/armada/armada_drv.c +++ b/drivers/gpu/drm/armada/armada_drv.c @@ -189,7 +189,6 @@ static struct drm_driver armada_drm_driver = { .load = armada_drm_load, .lastclose = armada_drm_lastclose, .unload = armada_drm_unload, - .set_busid = drm_platform_set_busid, .get_vblank_counter = drm_vblank_no_hw_counter, .enable_vblank = armada_drm_enable_vblank, .disable_vblank = armada_drm_disable_vblank, diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 1fa7619face3..ffd6a2795230 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -37,6 +37,64 @@ #include <linux/pci.h> #include <linux/export.h> +/** + * DOC: getunique and setversion story + * + * BEWARE THE DRAGONS! MIND THE TRAPDOORS! + * + * In an attempt to warn anyone else who's trying to figure out what's going + * on here, I'll try to summarize the story. First things first, let's clear up + * the names, because the kernel internals, libdrm and the ioctls are all named + * differently: + * + * - GET_UNIQUE ioctl, implemented by drm_getunique is wrapped up in libdrm + * through the drmGetBusid function. + * - The libdrm drmSetBusid function is backed by the SET_UNIQUE ioctl. All + * that code is nerved in the kernel with drm_invalid_op(). + * - The internal set_busid kernel functions and driver callbacks are + * exclusively use by the SET_VERSION ioctl, because only drm 1.0 (which is + * nerved) allowed userspace to set the busid through the above ioctl. + * - Other ioctls and functions involved are named consistently. + * + * For anyone wondering what's the difference between drm 1.1 and 1.4: Correctly + * handling pci domains in the busid on ppc. Doing this correctly was only + * implemented in libdrm in 2010, hence can't be nerved yet. No one knows what's + * special with drm 1.2 and 1.3. + * + * Now the actual horror story of how device lookup in drm works. At large, + * there's 2 different ways, either by busid, or by device driver name. + * + * Opening by busid is fairly simple: + * + * 1. First call SET_VERSION to make sure pci domains are handled properly. As a + * side-effect this fills out the unique name in the master structure. + * 2. Call GET_UNIQUE to read out the unique name from the master structure, + * which matches the busid thanks to step 1. If it doesn't, proceed to try + * the next device node. + * + * Opening by name is slightly different: + * + * 1. Directly call VERSION to get the version and to match against the driver + * name returned by that ioctl. Note that SET_VERSION is not called, which + * means the the unique name for the master node just opening is _not_ filled + * out. This despite that with current drm device nodes are always bound to + * one device, and can't be runtime assigned like with drm 1.0. + * 2. Match driver name. If it mismatches, proceed to the next device node. + * 3. Call GET_UNIQUE, and check whether the unique name has length zero (by + * checking that the first byte in the string is 0). If that's not the case + * libdrm skips and proceeds to the next device node. Probably this is just + * copypasta from drm 1.0 times where a set unique name meant that the driver + * was in use already, but that's just conjecture. + * + * Long story short: To keep the open by name logic working, GET_UNIQUE must + * _not_ return a unique string when SET_VERSION hasn't been called yet, + * otherwise libdrm breaks. Even when that unique string can't ever change, and + * is totally irrelevant for actually opening the device because runtime + * assignable device instances were only support in drm 1.0, which is long dead. + * But the libdrm code in drmOpenByName somehow survived, hence this can't be + * broken. + */ + static int drm_version(struct drm_device *dev, void *data, struct drm_file *file_priv); diff --git a/drivers/gpu/drm/drm_platform.c b/drivers/gpu/drm/drm_platform.c index 644169e1a029..2c819ef90090 100644 --- a/drivers/gpu/drm/drm_platform.c +++ b/drivers/gpu/drm/drm_platform.c @@ -68,24 +68,6 @@ err_free: return ret; } -int drm_platform_set_busid(struct drm_device *dev, struct drm_master *master) -{ - int id; - - id = dev->platformdev->id; - if (id < 0) - id = 0; - - master->unique = kasprintf(GFP_KERNEL, "platform:%s:%02d", - dev->platformdev->name, id); - if (!master->unique) - return -ENOMEM; - - master->unique_len = strlen(master->unique); - return 0; -} -EXPORT_SYMBOL(drm_platform_set_busid); - /** * drm_platform_init - Register a platform device with the DRM subsystem * @driver: DRM device driver diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c index 3d4f56df8359..340d390306d8 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c @@ -496,7 +496,6 @@ static struct drm_driver etnaviv_drm_driver = { DRIVER_RENDER, .open = etnaviv_open, .preclose = etnaviv_preclose, - .set_busid = drm_platform_set_busid, .gem_free_object_unlocked = etnaviv_gem_free_object, .gem_vm_ops = &vm_ops, .prime_handle_to_fd = drm_gem_prime_handle_to_fd, diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c b/drivers/gpu/drm/exynos/exynos_drm_drv.c index 4a679fb9bb02..13d28d4229e2 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_drv.c +++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c @@ -407,7 +407,6 @@ static struct drm_driver exynos_drm_driver = { .preclose = exynos_drm_preclose, .lastclose = exynos_drm_lastclose, .postclose = exynos_drm_postclose, - .set_busid = drm_platform_set_busid, .get_vblank_counter = drm_vblank_no_hw_counter, .enable_vblank = exynos_drm_crtc_enable_vblank, .disable_vblank = exynos_drm_crtc_disable_vblank, diff --git a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c index ef2c32ec1616..1edd9bc80294 100644 --- a/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c +++ b/drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c @@ -171,7 +171,6 @@ static struct drm_driver kirin_drm_driver = { .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME | DRIVER_ATOMIC | DRIVER_HAVE_IRQ, .fops = &kirin_drm_fops, - .set_busid = drm_platform_set_busid, .gem_free_object_unlocked = drm_gem_cma_free_object, .gem_vm_ops = &drm_gem_cma_vm_ops, diff --git a/drivers/gpu/drm/imx/imx-drm-core.c b/drivers/gpu/drm/imx/imx-drm-core.c index 82656654fb21..7746418a4c08 100644 --- a/drivers/gpu/drm/imx/imx-drm-core.c +++ b/drivers/gpu/drm/imx/imx-drm-core.c @@ -407,7 +407,6 @@ static struct drm_driver imx_drm_driver = { .load = imx_drm_driver_load, .unload = imx_drm_driver_unload, .lastclose = imx_drm_driver_lastclose, - .set_busid = drm_platform_set_busid, .gem_free_object_unlocked = drm_gem_cma_free_object, .gem_vm_ops = &drm_gem_cma_vm_ops, .dumb_create = drm_gem_cma_dumb_create, diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c index 568fcc328f27..a02dc2b27739 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -722,7 +722,6 @@ static struct drm_driver msm_driver = { .open = msm_open, .preclose = msm_preclose, .lastclose = msm_lastclose, - .set_busid = drm_platform_set_busid, .irq_handler = msm_irq, .irq_preinstall = msm_irq_preinstall, .irq_postinstall = msm_irq_postinstall, diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c index c00ff6e786a3..295e7621cc68 100644 --- a/drivers/gpu/drm/nouveau/nouveau_drm.c +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c @@ -1070,7 +1070,6 @@ nouveau_drm_init(void) driver_pci = driver_stub; driver_pci.set_busid = drm_pci_set_busid; driver_platform = driver_stub; - driver_platform.set_busid = drm_platform_set_busid; nouveau_display_options(); diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c index 6b97011154bf..26c6134eb744 100644 --- a/drivers/gpu/drm/omapdrm/omap_drv.c +++ b/drivers/gpu/drm/omapdrm/omap_drv.c @@ -801,7 +801,6 @@ static struct drm_driver omap_drm_driver = { .unload = dev_unload, .open = dev_open, .lastclose = dev_lastclose, - .set_busid = drm_platform_set_busid, .get_vblank_counter = drm_vblank_no_hw_counter, .enable_vblank = omap_irq_enable_vblank, .disable_vblank = omap_irq_disable_vblank, diff --git a/drivers/gpu/drm/shmobile/shmob_drm_drv.c b/drivers/gpu/drm/shmobile/shmob_drm_drv.c index ee79264b5b6a..f0492603ea88 100644 --- a/drivers/gpu/drm/shmobile/shmob_drm_drv.c +++ b/drivers/gpu/drm/shmobile/shmob_drm_drv.c @@ -259,7 +259,6 @@ static struct drm_driver shmob_drm_driver = { | DRIVER_PRIME, .load = shmob_drm_load, .unload = shmob_drm_unload, - .set_busid = drm_platform_set_busid, .irq_handler = shmob_drm_irq, .get_vblank_counter = drm_vblank_no_hw_counter, .enable_vblank = shmob_drm_enable_vblank, diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c b/drivers/gpu/drm/tilcdc/tilcdc_drv.c index 308e197908fc..d27809372d54 100644 --- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c +++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.c @@ -541,7 +541,6 @@ static struct drm_driver tilcdc_driver = { .load = tilcdc_load, .unload = tilcdc_unload, .lastclose = tilcdc_lastclose, - .set_busid = drm_platform_set_busid, .irq_handler = tilcdc_irq, .irq_preinstall = tilcdc_irq_preinstall, .irq_postinstall = tilcdc_irq_postinstall, diff --git a/drivers/gpu/drm/virtio/virtgpu_drm_bus.c b/drivers/gpu/drm/virtio/virtgpu_drm_bus.c index 88a39165edd5..7f0e93f87a55 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drm_bus.c +++ b/drivers/gpu/drm/virtio/virtgpu_drm_bus.c @@ -27,16 +27,6 @@ #include "virtgpu_drv.h" -int drm_virtio_set_busid(struct drm_device *dev, struct drm_master *master) -{ - struct pci_dev *pdev = dev->pdev; - - if (pdev) { - return drm_pci_set_busid(dev, master); - } - return 0; -} - static void virtio_pci_kick_out_firmware_fb(struct pci_dev *pci_dev) { struct apertures_struct *ap; diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c index 5820b7020ae5..c13f70cfc461 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drv.c +++ b/drivers/gpu/drm/virtio/virtgpu_drv.c @@ -117,7 +117,6 @@ static const struct file_operations virtio_gpu_driver_fops = { static struct drm_driver driver = { .driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME | DRIVER_RENDER | DRIVER_ATOMIC, - .set_busid = drm_virtio_set_busid, .load = virtio_gpu_driver_load, .unload = virtio_gpu_driver_unload, .open = virtio_gpu_driver_open, diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h index acf556a35cb2..b18ef3111f0c 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drv.h +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h @@ -49,7 +49,6 @@ #define DRIVER_PATCHLEVEL 1 /* virtgpu_drm_bus.c */ -int drm_virtio_set_busid(struct drm_device *dev, struct drm_master *master); int drm_virtio_init(struct drm_driver *driver, struct virtio_device *vdev); struct virtio_gpu_object { diff --git a/include/drm/drmP.h b/include/drm/drmP.h index fd4e4391aee5..babec2e80760 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -1132,7 +1132,6 @@ extern int drm_pcie_get_max_link_width(struct drm_device *dev, u32 *mlw); /* platform section */ extern int drm_platform_init(struct drm_driver *driver, struct platform_device *platform_device); -extern int drm_platform_set_busid(struct drm_device *d, struct drm_master *m); /* returns true if currently okay to sleep */ static __inline__ bool drm_can_sleep(void) |