[PATCH 4.18 071/171] mach64: fix display corruption on big endian machines

Greg Kroah-Hartman
2018-11-19T16:42:25Z

From: Mikulas Patocka <mpatocka@redhat.com>

commit 3c6c6a7878d00a3ac997a779c5b9861ff25dfcc8 upstream.

The code for manual bit triple is not endian-clean. It builds the variable
"hostdword" using byte accesses, therefore we must read the variable with
"le32_to_cpu".

The patch also enables (hardware or software) bit triple only if the image
is monochrome (image->depth). If we want to blit full-color image, we
shouldn't use the triple code.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Ville Syrjälä <syrjala@sci.fi>
Cc: stable@vger.kernel.org
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/video/fbdev/aty/mach64_accel.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/video/fbdev/aty/mach64_accel.c
+++ b/drivers/video/fbdev/aty/mach64_accel.c
@@ -345,7 +345,7 @@ void atyfb_imageblit(struct fb_info *inf
* since Rage 3D IIc we have DP_HOST_TRIPLE_EN bit
* this hwaccelerated triple has an issue with not aligned data
*/
- if (M64_HAS(HW_TRIPLE) && image->width % 8 == 0)
+ if (image->depth == 1 && M64_HAS(HW_TRIPLE) && image->width % 8 == 0)
pix_width |= DP_HOST_TRIPLE_EN;
}

@@ -382,7 +382,7 @@ void atyfb_imageblit(struct fb_info *inf
src_bytes = (((image->width * image->depth) + 7) / 8) * image->height;

/* manual triple each pixel */
- if (info->var.bits_per_pixel == 24 && !(pix_width & DP_HOST_TRIPLE_EN)) {
+ if (image->depth == 1 && info->var.bits_per_pixel == 24 && !(pix_width & DP_HOST_TRIPLE_EN)) {
int inbit, outbit, mult24, byte_id_in_dword, width;
u8 *pbitmapin = (u8*)image->data, *pbitmapout;
u32 hostdword;
@@ -415,7 +415,7 @@ void atyfb_imageblit(struct fb_info *inf
}
}
wait_for_fifo(1, par);
- aty_st_le32(HOST_DATA0, hostdword, par);
+ aty_st_le32(HOST_DATA0, le32_to_cpu(hostdword), par);
}
} else {
u32 *pbitmap, dwords = (src_bytes + 3) / 4;