Strange problem with Haswell HD 4600 IGA and screen resolution

[Paul Livingston]

All,

I recently built a new desktop machine using a Shuttle SZ87R6, an I7-4770S and a Dell U2713HM monitor.  Did my initial HW burn-in and testing using a Fedora 20 KDE Spin Live CD (Kernel 3.11.10-301.fc20.x86_64 & KDE Systems settings v4.11.3) everything worked fine and the display resolution was 2560x1440 (native for the display).  The last of the parts came in (HD for secondary storage) and I finished the build and did an install and a full system update (Kernel 3.14.8-200.fc20.x86_64 and KDE System Settings v4.11.10, along with ~=750MB of other updates)  The display looked odd after rebooting and when I checked it was set to 1600x1200 (not only wrong resolution but wrong aspect ratio).

Checked the U2713HM OSD and found that while the max resolution was 2560x1440, current resolution was 1600x1200 and the interface was correctly reported (DVI-D).  Verified the interconnection was DVI-D to DVI-D via a dual link DVI cable.  Went back inside and rechecked the Display and Monitor settings in Systems Settings and maximum available resolution was 1600x1200 (which is what the display was set to). also noted that the Display and Monitor applet was reporting an HDMI interconnect vice the actual DVI-D.  Ran xrandr from the command line and found that while 1920x1200 was shown as an available resolution (at least the correct aspect ratio), I could not set it to that using the command line.   Scratched my head and spent several hours Googling to see if anyone else had run into this problem - no luck although there were some postings from roughly a year ago about people in the Win8 world having video problems with the HD 4600 IGA.  I then spent some time on the Intel site, found several conflicting threads on HD 4600 capability and did an explicit update to the latest version of the Intel video stack for Linux.  No change and still unable to reset video resolution or aspect ratio from within F20.  BTW, going back to the earlier kernel is not really an option as I wanted the privilege  escalation bug fix that came out in 3.14.6, however with the earlier kernel the resolution and aspect ratio is correct.

At this stage, I have pretty well established (at least in my own mind) that it is a SW vice a HW problem and it is entirely reproducible as when I reboot with the Live CD the 2560x1440 resolution comes up by default.  While at this point I rather strongly suspect the Intel i915 driver and video stack, it could also be either a KDE or an xorg or a kernel issue and I really don' know where to file a bug report since I can't nail down which SW is screwing up or what to try next short of installing a low TDP video card, which I would rather avoid. 

Any ideas, insight or suggestions would be most welcome.  

Paul Livingston
pml at accokeekwoods.com