Hi

Am 21.10.25 um 10:41 schrieb Mehdi Ben Hadj Khelifa:
On 10/21/25 7:51 AM, Thomas Zimmermann wrote:
Hi

Am 20.10.25 um 13:57 schrieb Mehdi Ben Hadj Khelifa:
Use drm_format_info_min_pitch() to calculate the framebuffer line pitch
instead of directly multiplying width and height. This aligns with DRM
helpers for determining per-line byte size and avoids manual assumptions
about bytes per pixel.

Suggested-by: Thomas Zimmermann <[email protected]>
Signed-off-by: Mehdi Ben Hadj Khelifa <[email protected]>
---
  drivers/gpu/drm/tiny/repaper.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tiny/repaper.c b/drivers/gpu/drm/tiny/ repaper.c
index 4824f863fdba..aeff49bc6ba7 100644
--- a/drivers/gpu/drm/tiny/repaper.c
+++ b/drivers/gpu/drm/tiny/repaper.c
@@ -517,6 +517,8 @@ static int repaper_fb_dirty(struct drm_framebuffer *fb, const struct iosys_map *
      unsigned int dst_pitch = 0;
      struct iosys_map dst;
      struct drm_rect clip;
+    const struct drm_format_info *info = fb->format;

This is the wrong format. You're allocating the output buffer here, but you're using the input format. IIUC the output format is DRM_FORMAT_R1. The input is _XRGB8888.

Ah. Thanks for clarification.I thought since it had the same output format. I will send a v3 shortly.> Best regards

Maybe just don't do it. This is just churn with no clear goal.

Best regards
Thomas

Thomas

+    size_t pitch;
      int idx, ret = 0;
      u8 *buf = NULL;
@@ -534,7 +536,9 @@ static int repaper_fb_dirty(struct drm_framebuffer *fb, const struct iosys_map *
      DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
            epd->factored_stage_time);
-    buf = kmalloc(fb->width * fb->height / 8, GFP_KERNEL);
+    pitch = drm_format_info_min_pitch(info, 0, fb->width);
+
+    buf = kmalloc_array(fb->height, pitch, GFP_KERNEL);
      if (!buf) {
          ret = -ENOMEM;
          goto out_exit;



--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)


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