From 830b2e55dfe0b120f0ebaf81e3b89d2dbee4e0e6 Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Thu, 13 Aug 2026 16:46:49 -0400 Subject: [PATCH] drm/nouveau: Fix drm_driver struct/nouveau.atomic parameter handling The way we handled the nouveau.atomic module parameter before was fairly broken, and had a number of issues: - It was only ever actually parsed in the case of PCI devices. - When nouveau.atomic was enabled, it would add the cap for atomic modesetting to the global driver_pci structure. This meant that if one GPU on a system supported atomic and another didn't, it would still get enabled for both. Looking into this exposed further silliness in the way that we actually handle the drm_driver struct. We have one global structure for platform devices, and another for PCI devices - both of which are literally identical. So before we start preparing to enable atomic modesetting by default, let's fix this. Instead of sharing driver_pci and driver_platform, we instead create driver_legacy_kms and driver_atomic_kms, each of which is identical except for the DRIVER_ATOMIC capabilities flag, and then assign either depending on the nouveau_atomic module parameter. Doing this is also preferable, as the next step for enabling atomic modesetting by default will be ensuring that we don't enable it for legacy devices that still don't support it. This requires only checking the atomic modesetting module parameter after the NVKM device is ready, as this allows us to check the GPU family that nouveau is running on. Signed-off-by: Lyude Paul Reviewed-by: Dave Airlie Link: https://patch.msgid.link/20260813204803.2097176-4-lyude@redhat.com --- drivers/gpu/drm/nouveau/nouveau_drm.c | 98 ++++++++++++++++----------- 1 file changed, 57 insertions(+), 41 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c index 451009adee0d..d021a3049be1 100644 --- a/drivers/gpu/drm/nouveau/nouveau_drm.c +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c @@ -111,9 +111,8 @@ MODULE_PARM_DESC(runpm, "disable (0), force enable (1), optimus only default (-1 static int nouveau_runtime_pm = -1; module_param_named(runpm, nouveau_runtime_pm, int, 0400); -static struct drm_driver driver_stub; -static struct drm_driver driver_pci; -static struct drm_driver driver_platform; +static const struct drm_driver driver_legacy_kms; +static const struct drm_driver driver_atomic_kms; #ifdef CONFIG_DEBUG_FS struct dentry *nouveau_debugfs_root; @@ -727,8 +726,7 @@ nouveau_drm_device_del(struct nouveau_drm *drm) } static struct nouveau_drm * -nouveau_drm_device_new(const struct drm_driver *drm_driver, struct device *parent, - struct nvkm_device *device) +nouveau_drm_device_new(struct device *parent, struct nvkm_device *device) { static const struct nvif_mclass mmus[] = { @@ -737,16 +735,21 @@ nouveau_drm_device_new(const struct drm_driver *drm_driver, struct device *paren { NVIF_CLASS_MMU_NV04 , -1 }, {} }; + const struct drm_driver *driver; struct nouveau_drm *drm; int ret; + if (nouveau_atomic) + driver = &driver_atomic_kms; + else + driver = &driver_legacy_kms; + drm = kzalloc_obj(*drm); if (!drm) return ERR_PTR(-ENOMEM); drm->nvkm = device; - - drm->dev = drm_dev_alloc(drm_driver, parent); + drm->dev = drm_dev_alloc(driver, parent); if (IS_ERR(drm->dev)) { ret = PTR_ERR(drm->dev); kfree(drm); @@ -874,16 +877,13 @@ static int nouveau_drm_probe(struct pci_dev *pdev, return ret; /* Remove conflicting drivers (vesafb, efifb etc). */ - ret = aperture_remove_conflicting_pci_devices(pdev, driver_pci.name); + ret = aperture_remove_conflicting_pci_devices(pdev, DRIVER_NAME); if (ret) goto fail_nvkm; pci_set_master(pdev); - if (nouveau_atomic) - driver_pci.driver_features |= DRIVER_ATOMIC; - - drm = nouveau_drm_device_new(&driver_pci, &pdev->dev, device); + drm = nouveau_drm_device_new(&pdev->dev, device); if (IS_ERR(drm)) { ret = PTR_ERR(drm); goto fail_nvkm; @@ -1360,35 +1360,54 @@ nouveau_driver_fops = { .fop_flags = FOP_UNSIGNED_OFFSET, }; -static struct drm_driver -driver_stub = { - .driver_features = DRIVER_GEM | - DRIVER_SYNCOBJ | DRIVER_SYNCOBJ_TIMELINE | - DRIVER_MODESET | - DRIVER_RENDER, - .open = nouveau_drm_open, - .postclose = nouveau_drm_postclose, - -#if defined(CONFIG_DEBUG_FS) - .debugfs_init = nouveau_drm_debugfs_init, +#ifdef CONFIG_DEBUG_FS +#define NOUVEAU_DEBUGFS_OPS .debugfs_init = nouveau_drm_debugfs_init, +#else +#define NOUVEAU_DEBUGFS_OPS #endif - .ioctls = nouveau_ioctls, - .num_ioctls = ARRAY_SIZE(nouveau_ioctls), - .fops = &nouveau_driver_fops, +#define NOUVEAU_DRIVER_OPS \ + .open = nouveau_drm_open, \ + .postclose = nouveau_drm_postclose, \ + \ + NOUVEAU_DEBUGFS_OPS \ + \ + .ioctls = nouveau_ioctls, \ + .num_ioctls = ARRAY_SIZE(nouveau_ioctls), \ + .fops = &nouveau_driver_fops, \ + \ + .gem_prime_import_sg_table = nouveau_gem_prime_import_sg_table, \ + \ + .dumb_create = nouveau_display_dumb_create, \ + .dumb_map_offset = drm_gem_ttm_dumb_map_offset, \ + \ + DRM_FBDEV_TTM_DRIVER_OPS, \ + \ + .name = DRIVER_NAME, \ + .desc = DRIVER_DESC, \ + .major = DRIVER_MAJOR, \ + .minor = DRIVER_MINOR, \ + .patchlevel = DRIVER_PATCHLEVEL - .gem_prime_import_sg_table = nouveau_gem_prime_import_sg_table, +static const struct drm_driver +driver_legacy_kms = { + .driver_features = DRIVER_GEM + | DRIVER_SYNCOBJ + | DRIVER_SYNCOBJ_TIMELINE + | DRIVER_MODESET + | DRIVER_RENDER, + NOUVEAU_DRIVER_OPS, +}; - .dumb_create = nouveau_display_dumb_create, - .dumb_map_offset = drm_gem_ttm_dumb_map_offset, - - DRM_FBDEV_TTM_DRIVER_OPS, - - .name = DRIVER_NAME, - .desc = DRIVER_DESC, - .major = DRIVER_MAJOR, - .minor = DRIVER_MINOR, - .patchlevel = DRIVER_PATCHLEVEL, +static const struct drm_driver +driver_atomic_kms = { + .driver_features = DRIVER_GEM + | DRIVER_SYNCOBJ + | DRIVER_SYNCOBJ_TIMELINE + | DRIVER_MODESET + | DRIVER_RENDER + | DRIVER_ATOMIC, + NOUVEAU_DRIVER_OPS, }; static struct pci_device_id @@ -1457,7 +1476,7 @@ nouveau_platform_device_create(const struct nvkm_device_tegra_func *func, if (err) goto err_free; - drm = nouveau_drm_device_new(&driver_platform, &pdev->dev, *pdevice); + drm = nouveau_drm_device_new(&pdev->dev, *pdevice); if (IS_ERR(drm)) { err = PTR_ERR(drm); goto err_free; @@ -1482,9 +1501,6 @@ nouveau_drm_init(void) { int ret; - driver_pci = driver_stub; - driver_platform = driver_stub; - nouveau_display_options(); if (nouveau_modeset == -1) {