diff options
| author | Lv Zheng <lv.zheng@intel.com> | 2014-10-29 11:33:43 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-10-29 16:48:33 +0100 |
| commit | df9ff91801da603079018f21a9412385b62f0f8e (patch) | |
| tree | 29a919ab670954ab9c7c4b702d58891dbd932135 /drivers/acpi/ec.c | |
| parent | cac7f2429872d3733dc3f9915857b1691da2eb2f (diff) | |
| download | lwn-df9ff91801da603079018f21a9412385b62f0f8e.tar.gz lwn-df9ff91801da603079018f21a9412385b62f0f8e.zip | |
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: 558e4736f2e1b0e6323adf7a5e4df77ed6cfc1a4.
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: 3afcf2ece453e1a8c2c6de19cdf06da3772a1b08
Subject: ACPI / EC: Add support to disallow QR_EC to be issued when
SCI_EVT isn't set
commit 558e4736f2e1b0e6323adf7a5e4df77ed6cfc1a4 can be reverted.
Fixes: 558e4736f2e1 (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>
Diffstat (limited to 'drivers/acpi/ec.c')
| -rw-r--r-- | drivers/acpi/ec.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index 3d304ff7f095..31b699f2d088 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -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; |