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Subject[PATCH 3.11 104/128] ACPI / EC: Remove duplicated ec_wait_ibf0() waiter
Date
3.11.10.14 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lv Zheng <lv.zheng@intel.com>

commit 9b80f0f73ae1583c22325ede341c74195847618c upstream.

After we've added the first command byte write into advance_transaction(),
the IBF=0 waiter is duplicated with the command completion waiter
implemented in the ec_poll() because:
If IBF=1 blocked the first command byte write invoked in the task
context ec_poll(), it would be kicked off upon IBF=0 interrupt or timed
out and retried again in the task context.

Remove this seperate and duplicate IBF=0 waiter. By doing so we can
reduce the overall number of times to access the EC_SC(R) status
register.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=70891
Link: https://bugzilla.kernel.org/show_bug.cgi?id=63931
Link: https://bugzilla.kernel.org/show_bug.cgi?id=59911
Reported-and-tested-by: Gareth Williams <gareth@garethwilliams.me.uk>
Reported-and-tested-by: Hans de Goede <jwrdegoede@fedoraproject.org>
Reported-by: Barton Xu <tank.xuhan@gmail.com>
Tested-by: Steffen Weber <steffen.weber@gmail.com>
Tested-by: Arthur Chen <axchen@nvidia.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
[ luis: backported to 3.11: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
drivers/acpi/ec.c | 27 +--------------------------
1 file changed, 1 insertion(+), 26 deletions(-)

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 02090c6095fe..59bf2d016fd1 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -288,23 +288,6 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
return ret;
}

-static int ec_check_ibf0(struct acpi_ec *ec)
-{
- u8 status = acpi_ec_read_status(ec);
- return (status & ACPI_EC_FLAG_IBF) == 0;
-}
-
-static int ec_wait_ibf0(struct acpi_ec *ec)
-{
- unsigned long delay = jiffies + msecs_to_jiffies(ec_delay);
- /* interrupt wait manually if GPE mode is not active */
- while (time_before(jiffies, delay))
- if (wait_event_timeout(ec->wait, ec_check_ibf0(ec),
- msecs_to_jiffies(1)))
- return 0;
- return -ETIME;
-}
-
static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
{
int status;
@@ -325,12 +308,6 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
goto unlock;
}
}
- if (ec_wait_ibf0(ec)) {
- pr_err(PREFIX "input buffer is not empty, "
- "aborting transaction\n");
- status = -ETIME;
- goto end;
- }
pr_debug(PREFIX "transaction start (cmd=0x%02x, addr=0x%02x)\n",
t->command, t->wdata ? t->wdata[0] : 0);
/* disable GPE during transaction if storm is detected */
@@ -354,7 +331,6 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
}
pr_debug(PREFIX "transaction end\n");
-end:
if (ec->global_lock)
acpi_release_global_lock(glk);
unlock:
@@ -680,8 +656,7 @@ static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
spin_lock_irqsave(&ec->lock, flags);
advance_transaction(ec);
spin_unlock_irqrestore(&ec->lock, flags);
- if (ec_transaction_completed(ec) &&
- (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) == 0) {
+ if (ec_transaction_completed(ec)) {
wake_up(&ec->wait);
ec_check_sci(ec, acpi_ec_read_status(ec));
}
--
1.9.1


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