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    Subject[PATCH 5.4 083/151] tpm_tis: Disable interrupts on ThinkPad T490s
    Date
    From: Jerry Snitselaar <jsnitsel@redhat.com>

    [ Upstream commit b154ce11ead925de6a94feb3b0317fafeefa0ebc ]

    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: Peter Huewe <peterhuewe@gmx.de>
    Cc: Jason Gunthorpe <jgg@ziepe.ca>
    Cc: Hans de Goede <hdegoede@redhat.com>
    Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
    Reviewed-by: James Bottomley <James.Bottomley@HansenPartnership.com>
    Reviewed-by: Hans de Goede <hdegoede@redhat.com>
    Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
    Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    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 e7df342a317d6..c722e3b3121a8 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;
    --
    2.27.0


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