Hi Jakub,
My Lenovo T490s with i7-8665U had been marking TSC as unstable since v5.13, resulting in very sluggish desktop experience...
Kernel logs show:
clocksource: timekeeping watchdog on CPU3: hpet read-back delay of 316000ns, attempt 4, marking unstable tsc: Marking TSC unstable due to clocksource watchdog TSC found unstable after boot, most likely due to broken BIOS. Use 'tsc=unstable'. sched_clock: Marking unstable (14539801827657, -530891666)<-(14539319241737, -48307500) clocksource: Checking clocksource tsc synchronization from CPU 3 to CPUs 0-2,6-7. clocksource: Switched to clocksource hpet
I have a 8086:3e34 bridge, also known as "Host bridge: Intel Corporation Coffee Lake HOST and DRAM Controller (rev 0c)". Add it to the list.
We should perhaps consider applying this quirk more widely. The Intel documentation does not list my device [1], but linuxhw [2] does, and it seems to list a few more bridges we do not currently cover (3e31, 3ecc, 3e35, 3e0f).
I wish someone from Intel would be a little more forthcoming and chimed in about the other devices. I guess, we will cross that bridge when we get to it, so to speak.
[1] https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/8th-... [2] https://github.com/linuxhw/DevicePopulation/blob/master/README.md
Cc: stable@vger.kernel.org # v5.13+ Signed-off-by: Jakub Kicinski kuba@kernel.org
v2: - add the dmesg output
arch/x86/kernel/early-quirks.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c index 38837dad46e6..7d2de04f8750 100644 --- a/arch/x86/kernel/early-quirks.c +++ b/arch/x86/kernel/early-quirks.c @@ -716,6 +716,8 @@ static struct chipset early_qrk[] __initdata = { PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet}, { PCI_VENDOR_ID_INTEL, 0x3e20, PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet},
- { PCI_VENDOR_ID_INTEL, 0x3e34,
PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet},
Thank you!
Acked-by: Krzysztof Wilczyński kw@linux.com
Krzysztof