I realize that nVidia's aren't the preferred video card, but (being divorce-poor) one sometimes has to make do with what one has. :)
With my on-board nVidia (GeForce7100) and the nouveau driver (on both Tails and Qubes), things work okay, then suddenly at some random point the screen gets filled with diagonal line garbage, and things are unresponsive. (The system seems to still be running, but the screen is pooched and keyboard seems unresponsive, and no Alt-F1'ing or whatever will get it back. Processes still seem to be running though, and the ethernet light is blinking normally as traffic goes in an out, etc.) So I put in a PCI card, nVidia Geforce 7300, which seems solid, works perfectly under Tails. However, under Qubes, I experience random screen corruption. See: https://i.imgur.com/ovEFgYO.png It's usually fewer horizontal lines than in that snap, but I thought I'd include an extreme example to show the problem. It usually happens when the system is a bit busier CPU-wise/memory-wise, but otherwise functioning fine. Moving the window, or switching to another window and back, clears up the corruption. Screen corruption like that could be a sign of some wild pointer or other memory management bug, so I thought I'd bring it up. The paranoid half of me (okay, okay, I'll admit, it's more than half) worries it might be some attempted DMA attack. (I've been, and continue to be, the subject of some rather high-end professional hacking over the years, which adds to the concern.) I've read about attacks where screen memory is used to stuff code and run it to escalate privileges. And the nature of the garbage doesn't look like mis-placed screen stuff, but code or other binary data. Thankfully, if this is the case, the corruption seems contained to the AppVM. The garbage never spills outside an AppVm's window. It happens in both Redhat-23 and Debian-8 based AppVMs. I've never seen evidence of it in dom0/Qubes Manager and such. It realize it's *probably* not an attack, but I'd like to track down the nature of the problem whether it's a bug or an attack. I've read in another thread about video corruption caused by accessing memory who page has moved, and "echo 0 >/proc/sys/vm/compact_unevictable_allowed" supposedly helps. At first, I thought that made a difference, but ultimately, the problem is still there. Any ideas on what I can try, short of giving up and hunting down an ATI card or the like? (I might try the proprietary nVidia drivers when I get a chance to compile them. Not comfortable with grabbing binary versions for obvious reasons.) Thanks. You guys rock! -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To post to this group, send email to qubes-users@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/d571d11b44eaab879857416904323581.webmail%40localhost. For more options, visit https://groups.google.com/d/optout.
