This patchset is an attempt to try and catch tpm_tis devices that have interrupt storm issues, disable the interrupt, and use polling. In 2016 the tpm_tis interrupt code was accidently disabled, and polling was just being used. When we initially tried to enable interrupts again there were some reports of systems being hit with interrupt storms. It turned out that the ThinkPad T490s had misconfigured a gpio pin being used for the interrupt. The problem is more widespread though, with interrupt storms also being seen on other platforms and different TPM vendors. With the L490 the system hangs at tpm_tis initialization even with the detection code, so change the earlier detection code that used dmi to look for the T490s to instead look for the L490 and disable interrupts.
Since kstat_irqs needs to be exported to allow building of tpm_tis as a module, I've included a patch to change the i915_pmu code to use kstat_irqs where before it was using its own version. If this isn't desired it can be dropped.
I've been testing this on top of James' proposed patchset which re-enables interrupts for tpm_tis. With the patchsets applied it detects the problem on the T490s and on the Ice Lake development system where I found the issue. I have Lenovo verifying that the dmi detection code will now detect the L490 and avoid the hang it experiences. I'm also working on getting access to an L490 to see if I can figure out what the underlying issue is.
Changes from v2: - Export kstat_irqs to allow building tpm_tis as a module. - Change i915_pmu.c to use kstat_irqs instead of it's own version count_interrupts. - Change include from linux/kernel_stat.h to linux/irq.h. - Change dmi checking code to now look for L490 instead of T490s.
Changes from v1: - drop tpm_tis specific workqueue and use just system_w.
Jerry Snitselaar (4): irq: export kstat_irqs drm/i915/pmu: Use kstat_irqs to get interrupt count tpm_tis: Disable interrupts if interrupt storm detected tpm_tis: Disable Interrupts on the ThinkPad L490
Cc: Thomas Gleixner tglx@linutronix.de Cc: Jani Nikula jani.nikula@linux.intel.com Cc: Rodrigo Vivi rodrigo.vivi@intel.com Cc: David Airlie airlied@linux.ie Cc: Daniel Vetter daniel@ffwll.ch Cc: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Cc: Jarkko Sakkinen jarkko@kernel.org Cc: Jason Gunthorpe jgg@ziepe.ca Cc: Peter Huewe peterhuewe@gmx.de Cc: James Bottomley James.Bottomley@HansenPartnership.com Cc: Matthew Garrett mjg59@google.com Cc: Hans de Goede hdegoede@redhat.com Cc: linux-integrity@vger.kernel.org
drivers/char/tpm/tpm_tis.c | 4 ++-- drivers/char/tpm/tpm_tis_core.c | 27 +++++++++++++++++++++++++++ drivers/char/tpm/tpm_tis_core.h | 2 ++ drivers/gpu/drm/i915/i915_pmu.c | 18 +----------------- include/linux/irqdesc.h | 1 + kernel/irq/irqdesc.c | 1 + 6 files changed, 34 insertions(+), 19 deletions(-)