OK, Joshua! I do not promise anything. But I, out of (your) desperation, will try to find answers for you. If (no promise)...
If I (eventually) return back, I have only one condition for you: NEVER ask how I found (any future) answer for/to you! Thank you, Zoran On Thu, Mar 30, 2017 at 5:48 PM, Joshua Pincus <[email protected]> wrote: > Hi Zoran, > > Thanks for your reply. > > My situation is this: When the VM guest comes up the first time from a > system-level reset (aka power on), the Broadwell HD graphics device runs > fine. I see basic VGA both before and during the boot of Windows. Once > Windows boots, the HD graphics device is configured by Intel's driver and I > see hi-rez output. On a reboot of Windows within the VM, an FLR is > issued. When the guest comes back up, no VGA. Windows does boot but > provides no VGA output. If Windows needs to drop into VGA mode so that a > user can access the real-mode functionality of the recovery console, still > no VGA. > > It's only on Broadwell-based boards that we have this problem. If we > issue FLRs during the reset of the PCI bus for older Intel boards, no > problem. We get VGA. Something involved with the FLR is messing up the > state of the hardware instead of actually returning the hardware to a > virgin state, akin to what you would get from a full system reset. > > I was wondering if anyone had seen this kind of behavior. We've tried > everything. We've manipulated all of the obvious HD graphics MMIO > registers involved with restoring VGA but nothing seems to work. > > Thanks, > JP > > On Thu, Mar 30, 2017 at 4:29 AM, Zoran Stojsavljevic < > [email protected]> wrote: > >> Hello Joshua, >> >> I'll ask similar question, considering UEFI (BIOS). I have no idea if you >> can issue somehow easy FLR (PCI Function Level Reset), but if you can, >> does this use case repeat itself? >> >> I found, related to BIOS, this pointer (http://www.tomshardware.co.uk >> /forum/278002-30-solved-what-capability-option-bios), since I do NOT >> recall this option in any (legacy and UEFI) of the BIOSes I used (and I >> used lot (>100) of them). Probably, did not pay too much attention, since I >> do not recall this option to be tested/used?! >> >> Zoran >> >> On Wed, Mar 29, 2017 at 10:49 PM, Joshua Pincus <[email protected]> >> wrote: >> >>> Hi, >>> >>> After performing just an FLR (PCI function level reset) of a Gen8 Intel >>> HD graphics device, there's no VGA output from the device, no matter what I >>> try to do. I've had coreboot reset the graphics control register, VGA >>> control, VGA display disable bit, etc. >>> >>> Has anyone seen anything like this? The only way I can get VGA restored >>> is by performing a system-level reset. But I just want to do an FLR. Any >>> ideas? >>> >>> Thanks, >>> JP >>> >>> -- >>> coreboot mailing list: [email protected] >>> https://www.coreboot.org/mailman/listinfo/coreboot >>> >> >> >
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