This patch cause "x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x064a2000-0x064a2fff], got write-back" problem. my 2GB ram Bay trail z3735f tablet runing on android-x86, "i915: fix remap_io_sg to verify the pgprot" cause this problem.
05-09 02:59:25.099 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x0640a000-0x0640dfff], got write-back 05-09 02:59:25.106 1440 1440 W hwc-gl-worker: EGL_ANDROID_native_fence_sync extension not supported 05-09 02:59:25.111 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x064a2000-0x064a2fff], got write-back 05-09 02:59:25.118 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x06400000-0x06404fff], got write-back 05-09 02:59:25.125 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x06405000-0x06408fff], got write-back 05-09 02:59:25.148 1440 1440 W hwc-gl-worker: EGL_ANDROID_native_fence_sync extension not supported 05-09 02:59:25.158 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x06542000-0x06542fff], got write-back 05-09 02:59:25.165 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x06499000-0x0649dfff], got write-back 05-09 02:59:25.171 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x0649e000-0x064a1fff], got write-back 05-09 02:59:25.177 1440 1440 W hwc-gl-worker: EGL_ANDROID_native_fence_sync extension not supported 05-09 02:59:25.183 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x065fa000-0x065fafff], got write-back 05-09 02:59:25.192 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x06539000-0x0653dfff], got write-back 05-09 02:59:25.199 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x0653e000-0x06541fff], got write-back 05-09 02:59:25.204 1440 1440 W hwc-gl-worker: EGL_ANDROID_native_fence_sync extension not supported 05-09 02:59:25.212 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x066a2000-0x066a2fff], got write-back 05-09 02:59:25.218 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x065f1000-0x065f5fff], got write-back 05-09 02:59:25.226 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x065f6000-0x065f9fff], got write-back
05-09 02:59:27.101 0 0 W x86/PAT : BootAnimation:1665 map pfn RAM range req write-combining for [mem 0x08a76000-0x08a76fff], got write-back 05-09 02:59:27.225 0 0 W x86/PAT : BootAnimation:1665 map pfn RAM range req write-combining for [mem 0x08a77000-0x08a7afff], got write-back 05-09 02:59:27.242 0 0 W x86/PAT : BootAnimation:1665 map pfn RAM range req write-combining for [mem 0x08bd0000-0x08bd0fff], got write-back 05-09 02:59:27.254 0 0 W x86/PAT : BootAnimation:1665 map pfn RAM range req write-combining for [mem 0x08bd1000-0x08bf0fff], got write-back 05-09 02:59:27.310 1440 1440 E drm-fb : Failed to get handle from prime fd: 25 05-09 02:59:27.322 0 0 W x86/PAT : BootAnimation:1665 map pfn RAM range req write-combining for [mem 0x080d5000-0x080d9fff], got write-back 05-09 02:59:27.322 0 0 W x86/PAT : BootAnimation:1665 map pfn RAM range req write-combining for [mem 0x080da000-0x080ddfff], got write-back 05-09 02:59:27.338 0 0 W x86/PAT : BootAnimation:1665 map pfn RAM range req write-combining for [mem 0x1b830000-0x1b83ffff], got write-back 05-09 02:59:27.338 0 0 W x86/PAT : BootAnimation:1665 map pfn RAM range req write-combining for [mem 0x1b76a000-0x1b76efff], got write-back 05-09 02:59:27.344 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x07e87000-0x07e8bfff], got write-back 05-09 02:59:27.349 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x07e8c000-0x07e90fff], got write-back 05-09 02:59:27.347 1440 1440 E drm-fb : Failed to get handle from prime fd: 25 05-09 02:59:27.361 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x1c123000-0x1c126fff], got write-back 05-09 02:59:27.361 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x1c127000-0x1c12afff], got write-back 05-09 02:59:27.362 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x1c12f000-0x1c13efff], got write-back 05-09 02:59:27.362 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x1c12b000-0x1c12efff], got write-back 05-09 02:59:27.364 1440 1440 E drm-fb : Failed to get handle from prime fd: 25 05-09 02:59:27.377 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x1c140000-0x1c144fff], got write-back 05-09 02:59:27.377 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x1c145000-0x1c148fff], got write-back 05-09 02:59:27.378 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x1c14b000-0x1c14ffff], got write-back 05-09 02:59:27.379 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x1c151000-0x1c155fff], got write-back 05-09 02:59:27.377 1440 1440 E drm-fb : Failed to get handle from prime fd: 25 05-09 02:59:27.393 0 0 W x86/PAT : surfaceflinger:1440 map pfn RAM range req write-combining for [mem 0x1c157000-0x1c15bfff], got write-back