[PATCH 5.17 0186/1126] drm/fb-helper: Mark screen buffers in system memory with FBINFO_VIRTFB

Greg Kroah-Hartman
2022-04-05T08:01:58Z

From: Thomas Zimmermann <tzimmermann@suse.de>

commit cd9f7f7ac5932129fe81b4c7559cfcb226ec7c5c upstream.

Mark screen buffers in system memory with FBINFO_VIRTFB. Otherwise, fbdev
deferred I/O marks mmap'ed areas of system memory with VM_IO. (There's an
inverse relationship between the two flags.)

For shadow buffers, also set the FBINFO_READS_FAST hint.

v3:
* change FB_ to FBINFO_ in commit description
v2:
* updated commit description (Daniel)
* added Fixes tag

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: d536540f304c ("drm/fb-helper: Add generic fbdev emulation .fb_probe function")
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v4.19+
Link: https://patchwork.freedesktop.org/patch/msgid/20220201115305.9333-1-tzimmermann@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/drm_fb_helper.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -2346,6 +2346,7 @@ static int drm_fb_helper_generic_probe(s
fbi->fbops = &drm_fbdev_fb_ops;
fbi->screen_size = sizes->surface_height * fb->pitches[0];
fbi->fix.smem_len = fbi->screen_size;
+ fbi->flags = FBINFO_DEFAULT;

drm_fb_helper_fill_info(fbi, fb_helper, sizes);

@@ -2353,19 +2354,21 @@ static int drm_fb_helper_generic_probe(s
fbi->screen_buffer = vzalloc(fbi->screen_size);
if (!fbi->screen_buffer)
return -ENOMEM;
+ fbi->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;

fbi->fbdefio = &drm_fbdev_defio;
-
fb_deferred_io_init(fbi);
} else {
/* buffer is mapped for HW framebuffer */
ret = drm_client_buffer_vmap(fb_helper->buffer, &map);
if (ret)
return ret;
- if (map.is_iomem)
+ if (map.is_iomem) {
fbi->screen_base = map.vaddr_iomem;
- else
+ } else {
fbi->screen_buffer = map.vaddr;
+ fbi->flags |= FBINFO_VIRTFB;
+ }

/*
* Shamelessly leak the physical address to user-space. As