Date: Tue, 26 May 2020 21:55:28 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Andriy Gapon <avg@freebsd.org> Cc: FreeBSD Current <current@freebsd.org> Subject: Re: acpi timer reads all ones [Was: efirtc + atrtc at the same time] Message-ID: <20200526185528.GA48478@kib.kiev.ua> In-Reply-To: <199c8845-e42c-fbee-3f13-0b3d0d7234dc@FreeBSD.org> References: <021d8df4-a4f8-620d-73b6-b6103d0bf7f1@FreeBSD.org> <199c8845-e42c-fbee-3f13-0b3d0d7234dc@FreeBSD.org>
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On Tue, May 26, 2020 at 06:22:13PM +0300, Andriy Gapon wrote: > On 25/05/2020 11:37, Andriy Gapon wrote: > > Also, there is another issue related to atrtc. > > When I have both drivers attached, and also when I have only atrtc attached > > (efi.rt.disabled=1), system clock jumps 10 minutes forward after each suspend / > > resume cycle (S0 -> S3 -> S0). That does not happen for reboot and shutdown > > cycles. I haven't investigated this deeper, but it is a curious problem. > > Actually, I was wrong. The problem can also occur with efirtc alone. > Also, sometimes there is a different problem where there are no callouts for a > period of time on the order of minutes. I tracked it to cc_lastscan being set > to a value greater than the current uptime. So, any scheduled callout gets > scheduled at cc_lastscan and it is a while before the uptime catches up. > > It seemed that both issues were connected and were a result of the uptime > jumping forward by some minutes and then jumping back to a sane value. > If something important happened during the weird period, like getting time of > day from hardware or invoking a callout, it lead to the observed effects. > > So, that gave me some ideas where to add debugging checks. > What I determined is that ACPI timer (ACPI-fast) could produce a reading of all > 1-s like happens when there is no hardware response. > > I caught one such instance and got a stack trace for it (but no crash dump > because devices had not resumed yet): > tc_windup() at tc_windup+0x318/frame 0xfffffe00a7a19300 > tc_ticktock() at tc_ticktock+0x4b/frame 0xfffffe00a7a19320 > hardclock() at hardclock+0x107/frame 0xfffffe00a7a19360 > handleevents() at handleevents+0xb3/frame 0xfffffe00a7a193a0 > timercb() at timercb+0x196/frame 0xfffffe00a7a193f0 > lapic_handle_timer() at lapic_handle_timer+0x98/frame 0xfffffe00a7a19420 > Xtimerint() at Xtimerint+0xb1/frame 0xfffffe00a7a19420 > --- interrupt, rip = 0xffffffff80b34500, rsp = 0xfffffe00a7a194f8, rbp = > 0xfffffe00a7a19540 --- > acpi_pcib_write_config() at acpi_pcib_write_config/frame 0xfffffe00a7a19540 > pci_cfg_restore() at pci_cfg_restore+0x2cc/frame 0xfffffe00a7a195a0 > pci_resume_child() at pci_resume_child+0xee/frame 0xfffffe00a7a195e0 > pci_resume() at pci_resume+0x49/frame 0xfffffe00a7a19630 > bus_generic_resume_child() at bus_generic_resume_child+0x43/frame 0xfffffe00a7a19650 > bus_generic_resume() at bus_generic_resume+0x29/frame 0xfffffe00a7a19680 > bus_generic_resume_child() at bus_generic_resume_child+0x43/frame 0xfffffe00a7a196a0 > bus_generic_resume() at bus_generic_resume+0x29/frame 0xfffffe00a7a196d0 > bus_generic_resume_child() at bus_generic_resume_child+0x43/frame 0xfffffe00a7a196f0 > bus_generic_resume() at bus_generic_resume+0x29/frame 0xfffffe00a7a19720 > bus_generic_resume_child() at bus_generic_resume_child+0x43/frame 0xfffffe00a7a19740 > root_resume() at root_resume+0x29/frame 0xfffffe00a7a19770 > acpi_EnterSleepState() at acpi_EnterSleepState+0x73b/frame 0xfffffe00a7a197f0 > acpi_AckSleepState() at acpi_AckSleepState+0x144/frame 0xfffffe00a7a19820 > devfs_ioctl() at devfs_ioctl+0xcb/frame 0xfffffe00a7a19870 > vn_ioctl() at vn_ioctl+0x132/frame 0xfffffe00a7a19980 > devfs_ioctl_f() at devfs_ioctl_f+0x1e/frame 0xfffffe00a7a199a0 > kern_ioctl() at kern_ioctl+0x27b/frame 0xfffffe00a7a19a00 > sys_ioctl() at sys_ioctl+0x123/frame 0xfffffe00a7a19ad0 > amd64_syscall() at amd64_syscall+0x140/frame 0xfffffe00a7a19bf0 > fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe00a7a19bf0 > > I am not sure if this is just a coincidence but it appears as if a write to some > PCI configuration register could temporarily interfere with access to the PM > timer I/O port. > Is that plausible? If something disabled a BAR, then typical response of x86 chipset for timed out read from PCIe is 0xfffff... .
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