Henrique de Moraes Holschuh wrote: > On Wed, 29 Oct 2008, Alan Jenkins wrote: > >> Henrique de Moraes Holschuh wrote: >> >>> On Tue, 28 Oct 2008, Alexey Starikovskiy wrote: >>> >>>> Alan Jenkins wrote: >>>> >>>>> <http://bugzilla.kernel.org/show_bug.cgi?id=11841> >>>>> "plenty of line "ACPI: EC: non-query interrupt received, >>>>> switching to interrupt mode" in dmesg" >>>>> >>>>> >>>> Probably, it is better to make pr_debug(). >>>> >>>> >>> Please don't do that. This code has had a lot of churn, and *regressions* >>> as of lately, and sometimes we only notice these because we see those >>> messages in the logs. Moving them to pr_debug() pretty much makes them >>> utterly useless in a large number of the cases they could be of help. >>> >>> Besides, I very much doubt we will stop seing EC interrupt crappage. Not >>> only our code is NOT good and resilient enough yet (if it were, there >>> wouldn't be so many patches flying about it), the vendors are obviously >>> getting this wrong at a fast rate. >>> >>> We need those messages. Rate-limit them, but don't hide them or move them >>> to pr_debug, please. >>> >> Please have a look at the dmesg attached to the bug. They're already >> rate-limited. >> > > If people are considering moving it to pr_debug, it is not rate-limited > enough (one per mode switch is not enough if the EC or the code is behaving > so bad that it switches modes too often)... > > >> When in GPE storm avoidance mode, they will trigger once for each >> transaction. Transactions happen frequently, and will happen >> continually once e.g. gnome-power-manager is polling the battery level. >> In this special case, they're not a useful message to users or >> blackbox-level testers; they are only useful as part of a full DEBUG >> trace that actually shows the transactions. >> > > Well, if they move to pr_debug _only_ when in GPE storm avoidance mode, AND > we get the logging of entering AND exiting GPE storm avoidance modes, that > would be quite acceptable, I think. > > >> My original patch suppresses the message in this particular case, but it >> preserves it for the common non-storm case, where it may provide useful >> information. And the message would still happen once on boot, before >> the GPE storm is detected. Unfortunately my patch also makes the driver >> a little less robust. If the robustness issue can be addressed, do you >> accept that it's a good idea to suppress the flood of duplicate messages >> reported in this bug? >> > > As I said above, if you supress them ONLY during GPE storm avoidance, then > yes, I am quite OK with it. > > But we really should have GPE storm avoidance events logged, if we don't do > that already. > > >> We already have... damn. I think you missed a more important omission. >> There _used_ to be a message that says we've switched to storm avoidance >> mode. However, it was removed in the latest re-write. This bug report >> suggests that a) the cause would have been more obvious if we had the >> GPE storm message, and b) the stormy case wasn't really tested so we >> really do need a message, in case it goes wrong. >> > > Indeed, that's bad, and needs to be fixed IMHO. > Alex, can we persuade you? Here are the two changes in code form (untested). ------------> ACPI: EC: make kernel messages more useful when GPE storm is detected Make sure we can tell if the GPE storm workaround gets activated, and avoid flooding the logs afterwards. diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index ef42316..139046c 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -286,7 +286,8 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR); } else if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags) && t->irq_count > ACPI_EC_STORM_THRESHOLD) { - pr_debug(PREFIX "GPE storm detected\n"); + pr_info(PREFIX "GPE storm detected, " + "transactions will use polling mode\n"); set_bit(EC_FLAGS_GPE_STORM, &ec->flags); } return ret; @@ -566,9 +567,15 @@ static u32 acpi_ec_gpe_handler(void *data) if (!test_bit(EC_FLAGS_GPE_MODE, &ec->flags) && !test_bit(EC_FLAGS_NO_GPE, &ec->flags)) { /* this is non-query, must be confirmation */ - if (printk_ratelimit()) - pr_info(PREFIX "non-query interrupt received," + if (!test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) { + if (printk_ratelimit()) + pr_info(PREFIX "non-query interrupt received," + " switching to interrupt mode\n"); + } else { + /* hush, STORM switches the mode every transaction */ + pr_debug(PREFIX "non-query interrupt received," " switching to interrupt mode\n"); + } set_bit(EC_FLAGS_GPE_MODE, &ec->flags); } return ACPI_INTERRUPT_HANDLED; -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
