[+cc Jan, author of 0e8ae5a6ff59, linux-pci] On Wed, Jan 26, 2022 at 08:18:12AM +0000, bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=215533 > > --- Comment #1 from joey.corleone@xxxxxxx --- > I accidentally sent the report prematurely. So here come my findings: > > Since 5.16 > (1) my system becomes unresponsive every couple of seconds (micro lags), which > makes it more or less unusable. > (2) wrong(?) CPU frequencies are reported. > > - 5.15 works fine. > - Starting from some commit in 5.17, it seems (1) is fixed (unsure), but > definitely not (2). > > I have bisected the kernel between 5.15 and 5.16, and found that the offending > commit is 0e8ae5a6ff5952253cd7cc0260df838ab4c21009 ("PCI/portdrv: Do not setup > up IRQs if there are no users"). Bisection log attached. > > Reverting this commit on linux-git[1] fixes both (1) and (2). > > Important notes: > - This regression was reported on a DELL XPS 9550 laptop by two users [2], so > it might be related strictly to that model. > - According to user mallocman, the issue can also be fixed by reverting the > BIOS version of the laptop to v1.12. > - The issue ONLY occurs when AC is plugged in (and stays there even when I > unplug it). > - When booting on battery power, there is no issue at all. > > You can easily observe the regression via: > > watch cat /sys/devices/system/cpu/cpu[0-9]*/cpufreq/scaling_cur_fre > > As soon as I plug in AC, all frequencies go up to values around 3248338 and > stay there even if I unplug AC. This does not happen at all when booted on > battery power. > > Also note: > - the laptop's fans are not really affected by the high frequencies. > - setting the governor to "powersave" has no effect on the frequencies (as > compared to when on battery power). > - lowering the maximum frequency manually works, but does not fix (1). > > [1] https://aur.archlinux.org/pkgbase/linux-git/ (pulled commits up to > 0280e3c58f92b2fe0e8fbbdf8d386449168de4a8). > [2] https://bbs.archlinux.org/viewtopic.php?id=273330 > > -- > You may reply to this email to add a comment. > > You are receiving this mail because: > You are watching the assignee of the bug.
