[PATCH 3.2 23/94] drm/vmwgfx: Fix incorrect write to read-only register v2:

[Ben Hutchings]

3.2.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Hellstrom <thellstrom@xxxxxxxxxx>

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@xxxxxxxxx>
Tested-by: Christopher Friedt <chrisfriedt@xxxxxxxxx>
Signed-off-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Reviewed-by: Jakob Bornecrantz <jakob@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_fb.c | 1 -
 1 file changed, 1 deletion(-)

--- 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
 		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);
 	}
 

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