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 <tzimmermann@xxxxxxx>
Fixes: 808a40b69468 ("drm/fbdev-dma: Implement damage handling and deferred I/O")
Reported-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
Closes: https://lore.kernel.org/all/23636953.6Emhk5qWAg@steina-w/
Reported-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Closes: https://lore.kernel.org/dri-devel/CACRpkdb+hb9AGavbWpY-=uQQ0apY9en_tWJioPKf_fAbXMP4Hg@xxxxxxxxxxxxxx/
Tested-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
Tested-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: Javier Martinez Canillas <javierm@xxxxxxxxxx>
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: Maxime Ripard <mripard@xxxxxxxxxx>
Reviewed-by: Simona Vetter <simona.vetter@xxxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
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;
--
2.46.0
