On Sat, Feb 13, 2016 at 06:03:31PM -0700, Alex Williamson wrote:
On Sat, 13 Feb 2016 19:20:32 -0500 "Kevin O'Connor" kevin@koconnor.net wrote:
This confuses me - why didn't the host system BIOS turn on the LCD panel during host bootup?
It turns off when we reset the device between VM instances or between VM boots. IGD supports Function Level Reset (FLR).
Another desktop IvyBridge system doesn't really care about the vBIOS so long as we don't ask it to output anything before the guest native drivers are loaded. If we could, I think we'd just enable vBIOS for laptop panel support, but that's really not an option, it's going to run as a boot option ROM as well, so we need to fix the issues that it generates there.
From my experience with coreboot, running the vga option rom multiple times during a given boot is very fragile. (By multiple times, I mean either the host running it and then a guest, or running it multiple times from multiple guests.) YMMV.
We do this regularly for graphics assignment, Nvidia, AMD, and now Intel. It generally works ok. Perhaps you've seen issues with the option ROM being run multiple times without resetting the device. I could certainly believe that.
Interesting. Using the FLR could be useful on some coreboot systems where users want to run the option rom twice. Thanks.
-Kevin