Alan Jenkins wrote:
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).
Well, I was the one who inserted all this printouts in the first place...
Then every second reader of dmesg, and there are quite a lot of those starts to
open a bug report -- "my system prints bla-bla"...
So, if there is demand to have this printed -- there is no objection from me.
------------>
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;
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