drm/vmwgfx: correct fb_fix_screeninfo.line_length

Previously, the vmwgfx_fb driver would allow users to call FBIOSET_VINFO, but it would not adjust
the FINFO properly, resulting in distorted screen rendering. The patch corrects that behaviour.

See https://bugs.gentoo.org/show_bug.cgi?id=494794 for examples.

Cc: stable@vger.kernel.org
Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
index 9699bd174ae4..a89ad938eacf 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
@@ -147,7 +147,7 @@ static int vmw_fb_check_var(struct fb_var_screeninfo *var,
         }
 
         if (!vmw_kms_validate_mode_vram(vmw_priv,
-                                        info->fix.line_length,
+                                        var->xres * var->bits_per_pixel/8,
                                         var->yoffset + var->yres)) {
                 DRM_ERROR("Requested geom can not fit in framebuffer\n");
                 return -EINVAL;
@@ -162,6 +162,8 @@ static int vmw_fb_set_par(struct fb_info *info)
         struct vmw_private *vmw_priv = par->vmw_priv;
         int ret;
 
+        info->fix.line_length = info->var.xres * info->var.bits_per_pixel/8;
+
         ret = vmw_kms_write_svga(vmw_priv, info->var.xres, info->var.yres,
                                  info->fix.line_length,
                                  par->bpp, par->depth);
@@ -177,6 +179,7 @@ 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);
         }