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Revert "ACPI / EC: Add support to disallow QR_EC to be issued before completing previous QR_EC" 

It is reported that the following commit breaks Samsung hardware:
 Commit: 558e4736f2.
 Subject: ACPI / EC: Add support to disallow QR_EC to be issued before
          completing previous QR_EC

Which means the Samsung behavior conflicts with the Acer behavior.

1. Samsung may behave like:
   [ +event 1 ] SCI_EVT set
   [ +event 2 ] SCI_EVT set
                              write QR_EC
                              read event
   [ -event 1 ] SCI_EVT clear
   Without the above commit, Samsung can work:
   [ +event 1 ] SCI_EVT set
   [ +event 2 ] SCI_EVT set
                              write QR_EC
                              CAN prepare next QR_EC as SCI_EVT=1
                              read event
   [ -event 1 ] SCI_EVT clear
                              write QR_EC
                              read event
   [ -event 2 ] SCI_EVT clear
   With the above commit, Samsung cannot work:
   [ +event 1 ] SCI_EVT set
   [ +event 2 ] SCI_EVT set
                              write QR_EC
                              read event
   [ -event 1 ] SCI_EVT clear
                              CANNOT prepare next QR_EC as SCI_EVT=0
2. Acer may behave like:
   [ +event 1 ] SCI_EVT set
   [ +event 2 ]
                              write QR_EC
                              read event
   [ -event 1 ] SCI_EVT clear
   [ +event 2 ] SCI_EVT set
   Without the above commit, Acer cannot work when there is only 1 event:
   [ +event 1 ] SCI_EVT set
                              write QR_EC
                              can prepared next QR_EC as SCI_EVT=1
                              read event
   [ -event 1 ] SCI_EVT clear
                              CANNOT write QR_EC as SCI_EVT=0
   With the above commit, Acer can work:
   [ +event 1 ] SCI_EVT set
   [ +event 2 ]
                              write QR_EC
                              read event
   [ -event 1 ] SCI_EVT set
                              can prepare next QR_EC because SCI_EVT=0
                              CAN write QR_EC as SCI_EVT=1

Since Acer can also work with only the following commit applied:
 Commit: 3afcf2ece4
 Subject: ACPI / EC: Add support to disallow QR_EC to be issued when
          SCI_EVT isn't set
commit 558e4736f2 can be reverted.

Fixes: 558e4736f2 (ACPI / EC: Add support to disallow QR_EC to be issued ...)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=44161
Reported-and-tested-by: Ortwin Glück <odi@odi.ch>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Cc: 3.17+ <stable@vger.kernel.org> # 3.17+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Lv Zheng 2014-10-29 11:33:43 +08:00 committed by Rafael J. Wysocki
parent cac7f24298
commit df9ff91801
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/acpi/ec.c
View File

@ -334,13 +334,13 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
pr_debug("***** Command(%s) started *****\n",
acpi_ec_cmd_string(t->command));
start_transaction(ec);
spin_unlock_irqrestore(&ec->lock, tmp);
ret = ec_poll(ec);
spin_lock_irqsave(&ec->lock, tmp);
if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
pr_debug("***** Event stopped *****\n");
}
spin_unlock_irqrestore(&ec->lock, tmp);
ret = ec_poll(ec);
spin_lock_irqsave(&ec->lock, tmp);
pr_debug("***** Command(%s) stopped *****\n",
acpi_ec_cmd_string(t->command));
ec->curr = NULL;