[PATCH v2 01/43] drm/fbdev-generic: Do not set physical framebuffer address

[PATCH v2 01/43] drm/fbdev-generic: Do not set physical framebuffer address

[Thomas Zimmermann]

Framebuffer memory is allocated via vzalloc() from non-contiguous
physical pages. The physical framebuffer start address is therefore
meaningless. Do not set it.

The value is not used within the kernel and only exported to userspace
on dedicated ARM configs. No functional change is expected.

v2:
- refer to vzalloc() in commit message (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: a5b44c4adb16 ("drm/fbdev-generic: Always use shadow buffering")
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Zack Rusin <zackr@vmware.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: <stable@vger.kernel.org> # v6.4+
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Zack Rusin <zack.rusin@broadcom.com>
Reviewed-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Tested-by: Sui Jingfeng <sui.jingfeng@linux.dev>
---
 drivers/gpu/drm/drm_fbdev_generic.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_fbdev_generic.c b/drivers/gpu/drm/drm_fbdev_generic.c
index be357f926faec..97e579c33d84a 100644
--- a/drivers/gpu/drm/drm_fbdev_generic.c
+++ b/drivers/gpu/drm/drm_fbdev_generic.c
@@ -113,7 +113,6 @@ static int drm_fbdev_generic_helper_fb_probe(struct drm_fb_helper *fb_helper,
 	/* screen */
 	info->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;
 	info->screen_buffer = screen_buffer;
-	info->fix.smem_start = page_to_phys(vmalloc_to_page(info->screen_buffer));
 	info->fix.smem_len = screen_size;
 
 	/* deferred I/O */
-- 
2.44.0

Re: [PATCH v2 01/43] drm/fbdev-generic: Do not set physical framebuffer address

[Maxime Ripard]

On Wed, 10 Apr 2024 15:01:57 +0200, Thomas Zimmermann wrote:
> Framebuffer memory is allocated via vzalloc() from non-contiguous
> physical pages. The physical framebuffer start address is therefore
> meaningless. Do not set it.
> 
> The value is not used within the kernel and only exported to userspace
> 
> [ ... ]

Acked-by: Maxime Ripard <mripard@kernel.org>

Thanks!
Maxime