drivers/gpu/drm/qxl/qxl_fb.c:162:15: error: variable ‘qxl_defio’

I've also encountered same problem, the solution for me is:

--- linux-3.10-rc3.old/drivers/gpu/drm/qxl/Kconfig 2013-05-27 18:06:27.534000000 +0400 +++ linux-3.10-rc3/drivers/gpu/drm/qxl/Kconfig 2013-05-27 15:19:59.300000000 +0400 @@ -1,6 +1,7 @@ config DRM_QXL tristate "QXL virtual GPU" depends on DRM && PCI + select FB_DEFERRED_IO select FB_SYS_FILLRECT select FB_SYS_COPYAREA select FB_SYS_IMAGEBLIT