ACPI / EC: Remove duplicated ec_wait_ibf0() waiter

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>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 1 insertions, 26 deletions

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index f09386e9745f..d016ea31b8e9 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -281,23 +281,6 @@ 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;
@@ -318,12 +301,6 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
                         goto unlock;
                 }
         }
-        if (ec_wait_ibf0(ec)) {
-                pr_err("input buffer is not empty, "
-                                "aborting transaction\n");
-                status = -ETIME;
-                goto end;
-        }
         pr_debug("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 */
@@ -347,7 +324,6 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
                 set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
         }
         pr_debug("transaction end\n");
-end:
         if (ec->global_lock)
                 acpi_release_global_lock(glk);
 unlock:
@@ -653,8 +629,7 @@ 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));
         }