4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mikulas Patocka mpatocka@redhat.com
commit c09bcc91bb94ed91f1391bffcbe294963d605732 upstream.
Reading the registers without waiting for engine idle returns unpredictable values. These unpredictable values result in display corruption - if atyfb_imageblit reads the content of DP_PIX_WIDTH with the bit DP_HOST_TRIPLE_EN set (from previous invocation), the driver would never ever clear the bit, resulting in display corruption.
We don't want to wait for idle because it would degrade performance, so this patch modifies the driver so that it never reads accelerator registers.
HOST_CNTL doesn't have to be read, we can just write it with HOST_BYTE_ALIGN because no other part of the driver cares if HOST_BYTE_ALIGN is set.
DP_PIX_WIDTH is written in the functions atyfb_copyarea and atyfb_fillrect with the default value and in atyfb_imageblit with the value set according to the source image data.
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 | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-)
--- a/drivers/video/fbdev/aty/mach64_accel.c +++ b/drivers/video/fbdev/aty/mach64_accel.c @@ -127,7 +127,7 @@ void aty_init_engine(struct atyfb_par *p
/* set host attributes */ wait_for_fifo(13, par); - aty_st_le32(HOST_CNTL, 0, par); + aty_st_le32(HOST_CNTL, HOST_BYTE_ALIGN, par);
/* set pattern attributes */ aty_st_le32(PAT_REG0, 0, par); @@ -233,7 +233,8 @@ void atyfb_copyarea(struct fb_info *info rotation = rotation24bpp(dx, direction); }
- wait_for_fifo(4, par); + wait_for_fifo(5, par); + aty_st_le32(DP_PIX_WIDTH, par->crtc.dp_pix_width, par); aty_st_le32(DP_SRC, FRGD_SRC_BLIT, par); aty_st_le32(SRC_Y_X, (sx << 16) | sy, par); aty_st_le32(SRC_HEIGHT1_WIDTH1, (width << 16) | area->height, par); @@ -269,7 +270,8 @@ void atyfb_fillrect(struct fb_info *info rotation = rotation24bpp(dx, DST_X_LEFT_TO_RIGHT); }
- wait_for_fifo(3, par); + wait_for_fifo(4, par); + aty_st_le32(DP_PIX_WIDTH, par->crtc.dp_pix_width, par); aty_st_le32(DP_FRGD_CLR, color, par); aty_st_le32(DP_SRC, BKGD_SRC_BKGD_CLR | FRGD_SRC_FRGD_CLR | MONO_SRC_ONE, @@ -284,7 +286,7 @@ void atyfb_imageblit(struct fb_info *inf { struct atyfb_par *par = (struct atyfb_par *) info->par; u32 src_bytes, dx = image->dx, dy = image->dy, width = image->width; - u32 pix_width_save, pix_width, host_cntl, rotation = 0, src, mix; + u32 pix_width, rotation = 0, src, mix;
if (par->asleep) return; @@ -296,8 +298,7 @@ void atyfb_imageblit(struct fb_info *inf return; }
- pix_width = pix_width_save = aty_ld_le32(DP_PIX_WIDTH, par); - host_cntl = aty_ld_le32(HOST_CNTL, par) | HOST_BYTE_ALIGN; + pix_width = par->crtc.dp_pix_width;
switch (image->depth) { case 1: @@ -370,12 +371,11 @@ void atyfb_imageblit(struct fb_info *inf mix = FRGD_MIX_D_XOR_S | BKGD_MIX_D; }
- wait_for_fifo(6, par); - aty_st_le32(DP_WRITE_MASK, 0xFFFFFFFF, par); + wait_for_fifo(5, par); aty_st_le32(DP_PIX_WIDTH, pix_width, par); aty_st_le32(DP_MIX, mix, par); aty_st_le32(DP_SRC, src, par); - aty_st_le32(HOST_CNTL, host_cntl, par); + aty_st_le32(HOST_CNTL, HOST_BYTE_ALIGN, par); aty_st_le32(DST_CNTL, DST_Y_TOP_TO_BOTTOM | DST_X_LEFT_TO_RIGHT | rotation, par);
draw_rect(dx, dy, width, image->height, par); @@ -424,8 +424,4 @@ void atyfb_imageblit(struct fb_info *inf aty_st_le32(HOST_DATA0, get_unaligned_le32(pbitmap), par); } } - - /* restore pix_width */ - wait_for_fifo(1, par); - aty_st_le32(DP_PIX_WIDTH, pix_width_save, par); }