drm/vmwgfx: Fix incorrect write to read-only register v2:

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: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
index 907c26ff17a54d75cd16a1a14ccb77f7c4f55f32..7f16ff28070c14ea44aa14325d92be051d590b75 100644 (file)
--- 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);
        }