On Thu, Oct 15, 2020 at 02:44:30PM -0700, Jerry Snitselaar wrote:
> There is a misconfiguration in the bios of the gpio pin used for the
> interrupt in the T490s. When interrupts are enabled in the tpm_tis
> driver code this results in an interrupt storm. This was initially
> reported when we attempted to enable the interrupt code in the tpm_tis
> driver, which previously wasn't setting a flag to enable it. Due to
> the reports of the interrupt storm that code was reverted and we went back
> to polling instead of using interrupts. Now that we know the T490s problem
> is a firmware issue, add code to check if the system is a T490s and
> disable interrupts if that is the case. This will allow us to enable
> interrupts for everyone else. If the user has a fixed bios they can
> force the enabling of interrupts with tpm_tis.interrupts=1 on the
> kernel command line.
>
> Cc: jarkko@xxxxxxxxxx
> Cc: Peter Huewe <peterhuewe@xxxxxx>
> Cc: Jason Gunthorpe <jgg@xxxxxxxx>
> Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
> Reviewed-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
I'll apply this and make it available in linux-next.
/Jarkko
> ---
> drivers/char/tpm/tpm_tis.c | 29 +++++++++++++++++++++++++++--
> 1 file changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
> index 0b214963539d..4ed6e660273a 100644
> --- a/drivers/char/tpm/tpm_tis.c
> +++ b/drivers/char/tpm/tpm_tis.c
> @@ -27,6 +27,7 @@
> #include <linux/of.h>
> #include <linux/of_device.h>
> #include <linux/kernel.h>
> +#include <linux/dmi.h>
> #include "tpm.h"
> #include "tpm_tis_core.h"
>
> @@ -49,8 +50,8 @@ static inline struct tpm_tis_tcg_phy *to_tpm_tis_tcg_phy(struct tpm_tis_data *da
> return container_of(data, struct tpm_tis_tcg_phy, priv);
> }
>
> -static bool interrupts = true;
> -module_param(interrupts, bool, 0444);
> +static int interrupts = -1;
> +module_param(interrupts, int, 0444);
> MODULE_PARM_DESC(interrupts, "Enable interrupts");
>
> static bool itpm;
> @@ -63,6 +64,28 @@ module_param(force, bool, 0444);
> MODULE_PARM_DESC(force, "Force device probe rather than using ACPI entry");
> #endif
>
> +static int tpm_tis_disable_irq(const struct dmi_system_id *d)
> +{
> + if (interrupts == -1) {
> + pr_notice("tpm_tis: %s detected: disabling interrupts.\n", d->ident);
> + interrupts = 0;
> + }
> +
> + return 0;
> +}
> +
> +static const struct dmi_system_id tpm_tis_dmi_table[] = {
> + {
> + .callback = tpm_tis_disable_irq,
> + .ident = "ThinkPad T490s",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> + DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T490s"),
> + },
> + },
> + {}
> +};
> +
> #if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
> static int has_hid(struct acpi_device *dev, const char *hid)
> {
> @@ -192,6 +215,8 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info)
> int irq = -1;
> int rc;
>
> + dmi_check_system(tpm_tis_dmi_table);
> +
> rc = check_acpi_tpm2(dev);
> if (rc)
> return rc;
> --
> 2.28.0
>
>
