diff options
| -rw-r--r-- | drivers/char/ipmi/kcs_bmc_aspeed.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/drivers/char/ipmi/kcs_bmc_aspeed.c b/drivers/char/ipmi/kcs_bmc_aspeed.c index 19c32bf50e0e..2dea8cd5a09a 100644 --- a/drivers/char/ipmi/kcs_bmc_aspeed.c +++ b/drivers/char/ipmi/kcs_bmc_aspeed.c @@ -406,13 +406,31 @@ static void aspeed_kcs_check_obe(struct timer_list *timer) static void aspeed_kcs_irq_mask_update(struct kcs_bmc_device *kcs_bmc, u8 mask, u8 state) { struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc); + int rc; + u8 str; /* We don't have an OBE IRQ, emulate it */ if (mask & KCS_BMC_EVENT_TYPE_OBE) { - if (KCS_BMC_EVENT_TYPE_OBE & state) - mod_timer(&priv->obe.timer, jiffies + OBE_POLL_PERIOD); - else + if (KCS_BMC_EVENT_TYPE_OBE & state) { + /* + * Given we don't have an OBE IRQ, delay by polling briefly to see if we can + * observe such an event before returning to the caller. This is not + * incorrect because OBF may have already become clear before enabling the + * IRQ if we had one, under which circumstance no event will be propagated + * anyway. + * + * The onus is on the client to perform a race-free check that it hasn't + * missed the event. + */ + rc = read_poll_timeout_atomic(aspeed_kcs_inb, str, + !(str & KCS_BMC_STR_OBF), 1, 100, false, + &priv->kcs_bmc, priv->kcs_bmc.ioreg.str); + /* Time for the slow path? */ + if (rc == -ETIMEDOUT) + mod_timer(&priv->obe.timer, jiffies + OBE_POLL_PERIOD); + } else { del_timer(&priv->obe.timer); + } } if (mask & KCS_BMC_EVENT_TYPE_IBF) { |