I debugged a bit further on the waking from sleep issue - it actually also happens when changing modes through xrandr so not really related to waking from S3, just turning off/on the display.
The display in the UX302LG/LA needs to be run at 24-bit apparently - the current intel-gfx code (including in drm-intel-nightly) is clamping to 18bpp due to the BIOS advertising such info in the VBT (the same behavior is seen with CSM and nonCSM mode). If you remove the clamping, then everything works (display up at boot, modesetting works, waking from sleep works) - you don't really need commit c26fe8e5eb34c18aa9ab60fcf4c3150663a52306 BTW, just removing the clamping to run the pipe at 24bpp fixes all the blank screen issues. This behavior was noted on other laptops as described in the intel-gfx bug: https://bugzilla.kernel.org/show_bug.cgi?id=59841 As you can see in the bug description above, the temporary solution that's been merged in 3.12 was this hack: https://bugzilla.kernel.org/attachment.cgi?id=111321&action=diff Not entirely sure why that is not working for the UX302LG/LA yet (in fact I don't see dp_get_config called at all for some reason, so the hack does not go into effect). ** Bug watch added: Linux Kernel Bug Tracker #59841 http://bugzilla.kernel.org/show_bug.cgi?id=59841 ** Patch added: "0001-i915-Ignore-eDP-clamping-to-BIOS-provided-VBT-value.patch" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1265544/+attachment/3946655/+files/0001-i915-Ignore-eDP-clamping-to-BIOS-provided-VBT-value.patch -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1265544 Title: 8086:0a16 [UX302LG] black screen on boot 3.12.0-7 Status in “linux” package in Ubuntu: In Progress Bug description: Same description/workaround as https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1263015 I tried both Enable CSM and non-CSM boot. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: linux-image-3.12.0-7-generic 3.12.0-7.15 ProcVersionSignature: Ubuntu 3.12.0-7.15-generic 3.12.4 Uname: Linux 3.12.0-7-generic x86_64 ApportVersion: 2.12.7-0ubuntu3 Architecture: amd64 Date: Thu Jan 2 09:59:33 2014 HibernationDevice: RESUME=UUID=e6458b44-fdb9-4db5-8cac-40ee0bbf9cf6 InstallationDate: Installed on 2013-12-31 (1 days ago) InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20131231) Lsusb: Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 004: ID 03eb:8a03 Atmel Corp. Bus 001 Device 003: ID 1bcf:2987 Sunplus Innovation Technology Inc. Bus 001 Device 002: ID 8087:07dc Intel Corp. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: ASUSTeK COMPUTER INC. UX302LG ProcFB: 0 simple ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.12.0-7-generic.efi.signed root=/dev/mapper/ubuntu--vg-root ro recovery nomodeset RelatedPackageVersions: linux-restricted-modules-3.12.0-7-generic N/A linux-backports-modules-3.12.0-7-generic N/A linux-firmware 1.117 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/30/2013 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: UX302LG.207 dmi.board.asset.tag: ATN12345678901234567 dmi.board.name: UX302LG dmi.board.vendor: ASUSTeK COMPUTER INC. dmi.board.version: 1.0 dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: ASUSTeK COMPUTER INC. dmi.chassis.version: 1.0 dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrUX302LG.207:bd10/30/2013:svnASUSTeKCOMPUTERINC.:pnUX302LG:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnUX302LG:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0: dmi.product.name: UX302LG dmi.product.version: 1.0 dmi.sys.vendor: ASUSTeK COMPUTER INC. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1265544/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
