From: Thomas Zimmermann <tzimmermann@xxxxxxx> 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@xxxxxxx> Fixes: d536540f304c ("drm/fb-helper: Add generic fbdev emulation .fb_probe function") Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx Cc: <stable@xxxxxxxxxxxxxxx> # v4.19+ Link: https://patchwork.freedesktop.org/patch/msgid/20220201115305.9333-1-tzimmermann@xxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 Patches currently in stable-queue which might be from tzimmermann@xxxxxxx are queue-5.17/fbdev-hot-unplug-firmware-fb-devices-on-forced-removal.patch queue-5.17/drm-fb-helper-mark-screen-buffers-in-system-memory-with-fbinfo_virtfb.patch queue-5.17/drm-simpledrm-add-panel-orientation-property-on-non-upright-mounted-lcd-panels.patch queue-5.17/mgag200-fix-memmapsl-configuration-in-gctl6-register.patch