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Subject[patch 43/46] ACPI: EC: wait for last write gpe
2.6.27-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Alexey Starikovskiy <astarikovskiy@suse.de>

commit dd15f8c42af09031e27da5b4d697ce925511f2e1 upstream.

There is a possibility that EC might break if next command is
issued within 1 us after write or burst-disable command.

Suggestd-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/acpi/ec.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)
--- 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 ac
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_
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(
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)
--


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