From 5a498d4d06d6d9bad76d8a50a7f8fe01670ad46f Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Wed, 4 Sep 2024 14:36:54 +0200 Subject: drm/fbdev-dma: Only install deferred I/O if necessary Deferred I/O requires struct page for framebuffer memory, which is not guaranteed for all DMA ranges. We thus only install deferred I/O if we have a framebuffer that requires it. A reported bug affected the ipu-v3 and pl111 drivers, which have video memory in either Normal or HighMem zones [ 0.000000] Zone ranges: [ 0.000000] Normal [mem 0x0000000010000000-0x000000003fffffff] [ 0.000000] HighMem [mem 0x0000000040000000-0x000000004fffffff] where deferred I/O only works correctly with HighMem. See the Closes tags for bug reports. v2: - test if screen_buffer supports deferred I/O (Sima) Signed-off-by: Thomas Zimmermann Fixes: 808a40b69468 ("drm/fbdev-dma: Implement damage handling and deferred I/O") Reported-by: Alexander Stein Closes: https://lore.kernel.org/all/23636953.6Emhk5qWAg@steina-w/ Reported-by: Linus Walleij Closes: https://lore.kernel.org/dri-devel/CACRpkdb+hb9AGavbWpY-=uQQ0apY9en_tWJioPKf_fAbXMP4Hg@mail.gmail.com/ Tested-by: Alexander Stein Tested-by: Linus Walleij Cc: Thomas Zimmermann Cc: Javier Martinez Canillas Cc: Maarten Lankhorst Cc: Maxime Ripard Reviewed-by: Simona Vetter Reviewed-by: Linus Walleij Link: https://patchwork.freedesktop.org/patch/msgid/20240904123750.31206-1-tzimmermann@suse.de --- drivers/gpu/drm/drm_fbdev_dma.c | 83 +++++++++++++++++++++++++++++++---------- 1 file changed, 64 insertions(+), 19 deletions(-) diff --git a/drivers/gpu/drm/drm_fbdev_dma.c b/drivers/gpu/drm/drm_fbdev_dma.c index 7ef5a48c8029..b0602c4f3628 100644 --- a/drivers/gpu/drm/drm_fbdev_dma.c +++ b/drivers/gpu/drm/drm_fbdev_dma.c @@ -36,20 +36,11 @@ static int drm_fbdev_dma_fb_release(struct fb_info *info, int user) return 0; } -FB_GEN_DEFAULT_DEFERRED_DMAMEM_OPS(drm_fbdev_dma, - drm_fb_helper_damage_range, - drm_fb_helper_damage_area); - static int drm_fbdev_dma_fb_mmap(struct fb_info *info, struct vm_area_struct *vma) { struct drm_fb_helper *fb_helper = info->par; - struct drm_framebuffer *fb = fb_helper->fb; - struct drm_gem_dma_object *dma = drm_fb_dma_get_gem_obj(fb, 0); - if (!dma->map_noncoherent) - vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); - - return fb_deferred_io_mmap(info, vma); + return drm_gem_prime_mmap(fb_helper->buffer->gem, vma); } static void drm_fbdev_dma_fb_destroy(struct fb_info *info) @@ -70,13 +61,40 @@ static void drm_fbdev_dma_fb_destroy(struct fb_info *info) } static const struct fb_ops drm_fbdev_dma_fb_ops = { + .owner = THIS_MODULE, + .fb_open = drm_fbdev_dma_fb_open, + .fb_release = drm_fbdev_dma_fb_release, + __FB_DEFAULT_DMAMEM_OPS_RDWR, + DRM_FB_HELPER_DEFAULT_OPS, + __FB_DEFAULT_DMAMEM_OPS_DRAW, + .fb_mmap = drm_fbdev_dma_fb_mmap, + .fb_destroy = drm_fbdev_dma_fb_destroy, +}; + +FB_GEN_DEFAULT_DEFERRED_DMAMEM_OPS(drm_fbdev_dma, + drm_fb_helper_damage_range, + drm_fb_helper_damage_area); + +static int drm_fbdev_dma_deferred_fb_mmap(struct fb_info *info, struct vm_area_struct *vma) +{ + struct drm_fb_helper *fb_helper = info->par; + struct drm_framebuffer *fb = fb_helper->fb; + struct drm_gem_dma_object *dma = drm_fb_dma_get_gem_obj(fb, 0); + + if (!dma->map_noncoherent) + vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); + + return fb_deferred_io_mmap(info, vma); +} + +static const struct fb_ops drm_fbdev_dma_deferred_fb_ops = { .owner = THIS_MODULE, .fb_open = drm_fbdev_dma_fb_open, .fb_release = drm_fbdev_dma_fb_release, __FB_DEFAULT_DEFERRED_OPS_RDWR(drm_fbdev_dma), DRM_FB_HELPER_DEFAULT_OPS, __FB_DEFAULT_DEFERRED_OPS_DRAW(drm_fbdev_dma), - .fb_mmap = drm_fbdev_dma_fb_mmap, + .fb_mmap = drm_fbdev_dma_deferred_fb_mmap, .fb_destroy = drm_fbdev_dma_fb_destroy, }; @@ -89,6 +107,7 @@ static int drm_fbdev_dma_helper_fb_probe(struct drm_fb_helper *fb_helper, { struct drm_client_dev *client = &fb_helper->client; struct drm_device *dev = fb_helper->dev; + bool use_deferred_io = false; struct drm_client_buffer *buffer; struct drm_gem_dma_object *dma_obj; struct drm_framebuffer *fb; @@ -111,6 +130,15 @@ static int drm_fbdev_dma_helper_fb_probe(struct drm_fb_helper *fb_helper, fb = buffer->fb; + /* + * Deferred I/O requires struct page for framebuffer memory, + * which is not guaranteed for all DMA ranges. We thus only + * install deferred I/O if we have a framebuffer that requires + * it. + */ + if (fb->funcs->dirty) + use_deferred_io = true; + ret = drm_client_buffer_vmap(buffer, &map); if (ret) { goto err_drm_client_buffer_delete; @@ -130,7 +158,10 @@ static int drm_fbdev_dma_helper_fb_probe(struct drm_fb_helper *fb_helper, drm_fb_helper_fill_info(info, fb_helper, sizes); - info->fbops = &drm_fbdev_dma_fb_ops; + if (use_deferred_io) + info->fbops = &drm_fbdev_dma_deferred_fb_ops; + else + info->fbops = &drm_fbdev_dma_fb_ops; /* screen */ info->flags |= FBINFO_VIRTFB; /* system memory */ @@ -144,14 +175,28 @@ static int drm_fbdev_dma_helper_fb_probe(struct drm_fb_helper *fb_helper, } info->fix.smem_len = info->screen_size; - /* deferred I/O */ - fb_helper->fbdefio.delay = HZ / 20; - fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io; + /* + * Only set up deferred I/O if the screen buffer supports + * it. If this disagrees with the previous test for ->dirty, + * mmap on the /dev/fb file might not work correctly. + */ + if (!is_vmalloc_addr(info->screen_buffer) && info->fix.smem_start) { + unsigned long pfn = info->fix.smem_start >> PAGE_SHIFT; - info->fbdefio = &fb_helper->fbdefio; - ret = fb_deferred_io_init(info); - if (ret) - goto err_drm_fb_helper_release_info; + if (drm_WARN_ON(dev, !pfn_to_page(pfn))) + use_deferred_io = false; + } + + /* deferred I/O */ + if (use_deferred_io) { + fb_helper->fbdefio.delay = HZ / 20; + fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io; + + info->fbdefio = &fb_helper->fbdefio; + ret = fb_deferred_io_init(info); + if (ret) + goto err_drm_fb_helper_release_info; + } return 0; -- cgit v1.2.3-70-g09d2