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* [PATCH 2/5] drm/tegra: fbdev: Remove offset into framebuffer memory
       [not found] <20260421073646.144712-1-tzimmermann@suse.de>
@ 2026-04-21  7:29 ` Thomas Zimmermann
  0 siblings, 0 replies; only message in thread
From: Thomas Zimmermann @ 2026-04-21  7:29 UTC (permalink / raw)
  To: thierry.reding, mperttunen, airlied, simona, jonathanh
  Cc: dri-devel, linux-tegra, Thomas Zimmermann, stable

The screen_buffer field in struct fb_info contains the kernel address
of the first byte of framebuffer memory. Do not add the display offset.
This offset only describes scrolling during scanout.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: de2ba664c30f ("gpu: host1x: drm: Add memory manager and fb")
Cc: dri-devel@lists.freedesktop.org
Cc: linux-tegra@vger.kernel.org
Cc: <stable@vger.kernel.org> # v3.10+
---
 drivers/gpu/drm/tegra/fbdev.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/tegra/fbdev.c b/drivers/gpu/drm/tegra/fbdev.c
index 19e39fa54bfa..793849199783 100644
--- a/drivers/gpu/drm/tegra/fbdev.c
+++ b/drivers/gpu/drm/tegra/fbdev.c
@@ -76,7 +76,6 @@ int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 	struct fb_info *info = helper->info;
 	unsigned int bytes_per_pixel;
 	struct drm_framebuffer *fb;
-	unsigned long offset;
 	struct tegra_bo *bo;
 	size_t size;
 	int err;
@@ -115,9 +114,6 @@ int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 
 	drm_fb_helper_fill_info(info, helper, sizes);
 
-	offset = info->var.xoffset * bytes_per_pixel +
-		 info->var.yoffset * fb->pitches[0];
-
 	if (bo->pages) {
 		bo->vaddr = vmap(bo->pages, bo->num_pages, VM_MAP,
 				 pgprot_writecombine(PAGE_KERNEL));
@@ -129,9 +125,9 @@ int tegra_fbdev_driver_fbdev_probe(struct drm_fb_helper *helper,
 	}
 
 	info->flags |= FBINFO_VIRTFB;
-	info->screen_buffer = bo->vaddr + offset;
+	info->screen_buffer = bo->vaddr;
 	info->screen_size = size;
-	info->fix.smem_start = (unsigned long)(bo->iova + offset);
+	info->fix.smem_start = (unsigned long)(bo->iova);
 	info->fix.smem_len = size;
 
 	return 0;
-- 
2.53.0


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     [not found] <20260421073646.144712-1-tzimmermann@suse.de>
2026-04-21  7:29 ` [PATCH 2/5] drm/tegra: fbdev: Remove offset into framebuffer memory Thomas Zimmermann

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