Len Brown wrote:
applied to acpi-test.
we struggled with ec burst mode for a long time before enabling it
finally in 2005. have we had any problems with it since then
that might be addressed by this race?
hard to say, I was thinking that with the fast transaction, we may fall
into this window,
but it does not help in any of the current bug reports.
regards,
Alex.
thanks,
-Len
On Sun, 9 Nov 2008, Alexey Starikovskiy wrote:
There is a possibility that EC might break if next command is
issued within 1 us after write or burst-disable command.
This "possibility" was in EC driver for 3.5 years, after
451566f45a2e6cd10ba56e7220a9dd84ba3ef550.
References: http://marc.info/?l=linux-acpi&m=122616284402886&w=4
Cc: Zhao Yakui <yakui.zhao@xxxxxxxxx>
Signed-off-by: Alexey Starikovskiy <astarikovskiy@xxxxxxx>
---
drivers/acpi/ec.c | 21 +++++++++++++--------
1 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index e5dbe21..d6007ac 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -102,6 +102,7 @@ struct transaction {
u8 command;
u8 wlen;
u8 rlen;
+ bool done;
};
static struct acpi_ec {
@@ -178,7 +179,7 @@ static int ec_transaction_done(struct acpi_ec *ec)
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&ec->curr_lock, flags);
- if (!ec->curr || (!ec->curr->wlen && !ec->curr->rlen))
+ if (!ec->curr || ec->curr->done)
ret = 1;
spin_unlock_irqrestore(&ec->curr_lock, flags);
return ret;
@@ -195,17 +196,20 @@ static void gpe_transaction(struct acpi_ec *ec, u8 status)
acpi_ec_write_data(ec, *(ec->curr->wdata++));
--ec->curr->wlen;
} else
- /* false interrupt, state didn't change */
- ++ec->curr->irq_count;
-
+ goto err;
} else if (ec->curr->rlen > 0) {
if ((status & ACPI_EC_FLAG_OBF) == 1) {
*(ec->curr->rdata++) = acpi_ec_read_data(ec);
- --ec->curr->rlen;
+ if (--ec->curr->rlen == 0)
+ ec->curr->done = true;
} else
- /* false interrupt, state didn't change */
- ++ec->curr->irq_count;
- }
+ goto err;
+ } else if (ec->curr->wlen == 0 && (status & ACPI_EC_FLAG_IBF) == 0)
+ ec->curr->done = true;
+ goto unlock;
+err:
+ /* false interrupt, state didn't change */
+ ++ec->curr->irq_count;
unlock:
spin_unlock_irqrestore(&ec->curr_lock, flags);
}
@@ -265,6 +269,7 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
spin_lock_irqsave(&ec->curr_lock, tmp);
/* following two actions should be kept atomic */
t->irq_count = 0;
+ t->done = false;
ec->curr = t;
acpi_ec_write_cmd(ec, ec->curr->command);
if (ec->curr->command == ACPI_EC_COMMAND_QUERY)
--
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
--
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
--
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
