When using page list framebuffer, and using RGB888 format, some
pixels can cross the page boundaries, and this case was not handled,
leading to writing 1 or 2 bytes on the next virtual address.
Add a check and a specific function to handle this case.
Fixes: c9ff2808790f0 ("drm/panic: Add support to scanout buffer as array of pages")
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
---
drivers/gpu/drm/drm_panic.c | 46 +++++++++++++++++++++++++++++++++++--
1 file changed, 44 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
index bc5158683b2b..d4b6ea42db0f 100644
--- a/drivers/gpu/drm/drm_panic.c
+++ b/drivers/gpu/drm/drm_panic.c
@@ -174,6 +174,33 @@ static void drm_panic_write_pixel24(void *vaddr, unsigned int offset, u32 color)
*p = color & 0xff;
}
+/*
+ * Special case if the pixel crosses page boundaries
+ */
+static void drm_panic_write_pixel24_xpage(void *vaddr, struct page *next_page,
+ unsigned int offset, u32 color)
+{
+ u8 *vaddr2;
+ u8 *p = vaddr + offset;
+
+ vaddr2 = kmap_local_page_try_from_panic(next_page);
+
+ *p++ = color & 0xff;
+ color >>= 8;
+
+ if (offset == PAGE_SIZE - 1)
+ p = vaddr2;
+
+ *p++ = color & 0xff;
+ color >>= 8;
+
+ if (offset == PAGE_SIZE - 2)
+ p = vaddr2;
+
+ *p = color & 0xff;
+ kunmap_local(vaddr2);
+}
+
static void drm_panic_write_pixel32(void *vaddr, unsigned int offset, u32 color)
{
u32 *p = vaddr + offset;
@@ -231,7 +258,14 @@ static void drm_panic_blit_page(struct page **pages, unsigned int dpitch,
page = new_page;
vaddr = kmap_local_page_try_from_panic(pages[page]);
}
- if (vaddr)
+ if (!vaddr)
+ continue;
+
+ // Special case for 24bit, as a pixel might cross page boundaries
+ if (cpp == 3 && offset + 3 > PAGE_SIZE)
+ drm_panic_write_pixel24_xpage(vaddr, pages[page + 1],
+ offset, fg32);
+ else
drm_panic_write_pixel(vaddr, offset, fg32, cpp);
}
}
@@ -321,7 +355,15 @@ static void drm_panic_fill_page(struct page **pages, unsigned int dpitch,
page = new_page;
vaddr = kmap_local_page_try_from_panic(pages[page]);
}
- drm_panic_write_pixel(vaddr, offset, color, cpp);
+ if (!vaddr)
+ continue;
+
+ // Special case for 24bit, as a pixel might cross page boundaries
+ if (cpp == 3 && offset + 3 > PAGE_SIZE)
+ drm_panic_write_pixel24_xpage(vaddr, pages[page + 1],
+ offset, color);
+ else
+ drm_panic_write_pixel(vaddr, offset, color, cpp);
}
}
if (vaddr)
--
2.51.0