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drm/fbdev-dma: Only install deferred I/O if necessary

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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@suse.de>
Fixes: 808a40b694 ("drm/fbdev-dma: Implement damage handling and deferred I/O")
Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Closes: https://lore.kernel.org/all/23636953.6Emhk5qWAg@steina-w/
Reported-by: Linus Walleij <linus.walleij@linaro.org>
Closes: https://lore.kernel.org/dri-devel/CACRpkdb+hb9AGavbWpY-=uQQ0apY9en_tWJioPKf_fAbXMP4Hg@mail.gmail.com/
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Simona Vetter <simona.vetter@ffwll.ch>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240904123750.31206-1-tzimmermann@suse.de
This commit is contained in:
Thomas Zimmermann 2024-09-04 14:36:54 +02:00
parent 7de295d1a1
commit 5a498d4d06
1 changed files with 64 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

83
drivers/gpu/drm/drm_fbdev_dma.c
View File

@ -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;