<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - [SKL] Flashing black screen ([drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun)" href="https://bugs.freedesktop.org/show_bug.cgi?id=94605#c83">Comment # 83</a> on <a class="bz_bug_link bz_status_NEEDINFO " title="NEEDINFO - [SKL] Flashing black screen ([drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun)" href="https://bugs.freedesktop.org/show_bug.cgi?id=94605">bug 94605</a> from <a class="email" href="mailto:syphyr@gmail.com" title="syphyr@gmail.com">syphyr@gmail.com</a> <pre>(In reply to Mauro Santos from <a href="show_bug.cgi?id=94605#c81">comment #81</a>) > (In reply to Peter Wu from <a href="show_bug.cgi?id=94605#c80">comment #80</a>) > > Under what circumstances? Any special cmdline, patches or userspace > > packages? So far it seems to work for me (i7-6700HQ, Arch Linux, 4.8.6-1). > > I'm also on Arch with kernel 4.8.6-1. I have an i7-6500U. > > I guess the only "special" thing I have on the cmdline is intel_iommu=on, > but I don't see any memory errors as reported by syphyr. > > I have a way to avoid the problems, but that will limit the package c-state > to PC2, let me try to explain. > > If I do not do modifications to any of the kernel's defaults, the cpu never > gets to a package c-state lower than PC2 (1)(or higher, whichever way you > want to see it). > > If I enable sata ALPM then the cpu will to go into PC6 and that is when I > start to see the problem. > > Further, if I turn on auto suspend for a usb bluetooth device, the cpu will > now get into PC7 and I also see the problem in this case. I have not been > able to get the cpu to go into PC8~PC10 even when doing all the changes > recommended by powertop. > > (1) The cpu's datasheet states clearly that "Long term reliability cannot be > assured unless all the Low-Power Idle States are enabled.". I'm not sure if > this applies to package c-states but even if it doesn't I would like the cpu > to be as efficient as possible so that I get more time when using battery > and so that there is less heat and noise. Could you try replacing "intel_iommu=on" with: intel_iommu=igfx_off I also still have problems with intel_iommu=on.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are on the CC list for the bug.</li> <li>You are the assignee for the bug.</li> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>