From 3934185ba63feca6e80cc8b90f7d7f01cde78223 Mon Sep 17 00:00:00 2001 From: Linmao Li Date: Thu, 27 Aug 2026 17:39:48 +0800 Subject: [PATCH] fbdev: atafb: Restrict SuperBlitter to supported formats MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The SuperBlitter operations derive an integer byte count per pixel. The accelerated fill path handles only one-, two- and four-byte pixels. However, the operations are currently installed for every external framebuffer in SuperVidel RAM, including planar 1/2/4/8-bpp and 24-bpp truecolor modes accepted by the external video parser. For 1/2/4-bpp modes, the byte count becomes zero, so accelerated copies do nothing and fills fall through to 32-bit stores. Planar 8-bpp uses an incompatible memory layout. For 24-bpp modes, fills also use 32-bit stores despite advancing addresses by three bytes per pixel. These cases can corrupt the framebuffer beyond the requested rectangle. Enable the SuperBlitter operations only for the layouts they implement: 8-bpp packed pixels and 16/32-bpp truecolor. Keep the existing software operations for all other external formats. Fixes: d463633d63e6 ("fbdev: atafb: Add support for SuperVidel's SuperBlitter") Signed-off-by: Linmao Li Tested-by: Miro Kropáček Reviewed-by: Michael Schmitz Signed-off-by: Helge Deller --- drivers/video/fbdev/atafb.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/video/fbdev/atafb.c b/drivers/video/fbdev/atafb.c index 5bca34c45cef..c3011b61a94b 100644 --- a/drivers/video/fbdev/atafb.c +++ b/drivers/video/fbdev/atafb.c @@ -3360,7 +3360,11 @@ static int __init atafb_probe(struct platform_device *pdev) memset (screen_base, 0, external_len); /* framebuffer in SV RAM: enable the SuperBlitter */ - if (external_addr >= 0xa0000000) { + if (external_addr >= 0xa0000000 && + ((external_pmode == FB_TYPE_PACKED_PIXELS && + external_depth == 8) || + (external_pmode == -1 && + (external_depth == 16 || external_depth == 32)))) { svblit_regs = ioremap(SVBLIT_REGS_PHYS, 0x100); if (svblit_regs) { svblit_fw = svblit_rd(SVBLIT_VERSION) & 0x1ff;