[PATCH 3.12 087/170] drm/vmwgfx: Fix incorrect write to read-only register v2:

Jiri Slaby
2014-07-18T13:15:58Z

From: Thomas Hellstrom <thellstrom@vmware.com>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit 4e578080ed3262ed2c3985868539bc66218d25c0 upstream.

Commit "drm/vmwgfx: correct fb_fix_screeninfo.line_length", while fixing a
vmwgfx fbdev bug, also writes the pitch to a supposedly read-only register:
SVGA_REG_BYTES_PER_LINE, while it should be (and also in fact is) written to
SVGA_REG_PITCHLOCK.

This patch is Cc'd stable because of the unknown effects writing to this
register might have, particularly on older device versions.

v2: Updated log message.

Cc: Christopher Friedt <chrisfriedt@gmail.com>
Tested-by: Christopher Friedt <chrisfriedt@gmail.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/gpu/drm/vmwgfx/vmwgfx_fb.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
index 021b5227e783..1b0f34bd3a03 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
@@ -179,7 +179,6 @@ static int vmw_fb_set_par(struct fb_info *info)
vmw_write(vmw_priv, SVGA_REG_DISPLAY_POSITION_Y, info->var.yoffset);
vmw_write(vmw_priv, SVGA_REG_DISPLAY_WIDTH, info->var.xres);
vmw_write(vmw_priv, SVGA_REG_DISPLAY_HEIGHT, info->var.yres);
- vmw_write(vmw_priv, SVGA_REG_BYTES_PER_LINE, info->fix.line_length);
vmw_write(vmw_priv, SVGA_REG_DISPLAY_ID, SVGA_ID_INVALID);
}

--
2.0.0