On Mon, May 18, 2015 at 10:20:33AM +0800, Brad Campbell wrote:
> On 30/04/15 04:21, Chris Bainbridge wrote:
> >
> >Supporting _OSI("Darwin") caused the MacBook firmware to expose the SBS,
> >resulting in intermittent hangs of several minutes on boot, and failure
> >to detect or report the battery. Fix this by adding a 5us delay to the
> >start of each SMBUS transaction. This timing is the result of
> >experimentation - hangs were observed with 3us but never with 5us.
>
> G'day Chris,
>
> Using 4.1-rc3 (whatever git head was from a couple of days ago) I've still
> been seeing ACPI lockups on my Macbook Pro (11,1). It appears to take a
> couple of suspend/resume cycles but seems to happen within 24 hours of
> booting whereas before this patch it was easy to hit.
>
> As a test (and I do wonder if it'll lock up after I press send on this
> E-mail) I upped the delay to 10us and I've now been up for 1 day, 17:23 with
> the battery still responding to polling.
>
> To make it easier to reproduce, I've been running a script that polls the
> battery every 60 seconds.
>
> I figure I'll let it go for another couple of days, but I wanted to put this
> out there in case anyone else is seeing lockups after a longer period of
> uptime. The symptoms are the ACPI command just hangs as does 'cat
> /sys/class/power_supply/BAT0/status'. From there I can't suspend as the
> tasks can't be frozen and I just end up hard booting the machine.
>
> I've removed Len & Rafael from the cc.
>
> Regards,
> Brad
I used a patch similar to the following to test, it just runs the SBS
read in a loop. acpi_battery_get_info is run when the sbs module is
loaded. So start off with the 5us delay and a few runs through the loop
and verify you hit the hang, then increase the delay to 10us or whatever
and run the loop for a few thousand cycles until you're happy that
increasing the delay fixes the problem.
diff --git a/drivers/acpi/sbs.c b/drivers/acpi/sbs.c
index 01504c8..74f8596 100644
--- a/drivers/acpi/sbs.c
+++ b/drivers/acpi/sbs.c
@@ -361,16 +361,21 @@ static int acpi_manager_get_info(struct acpi_sbs *sbs)
static int acpi_battery_get_info(struct acpi_battery *battery)
{
int i, result = 0;
-
- for (i = 0; i < ARRAY_SIZE(info_readers); ++i) {
- result = acpi_smbus_read(battery->sbs->hc,
- info_readers[i].mode,
- ACPI_SBS_BATTERY,
- info_readers[i].command,
- (u8 *) battery +
- info_readers[i].offset);
- if (result)
- break;
+ int j;
+
+ for (j = 0; j < 1000; j++) {
+ for (i = 0; i < ARRAY_SIZE(info_readers); ++i) {
+ result = acpi_smbus_read(battery->sbs->hc,
+ info_readers[i].mode,
+ ACPI_SBS_BATTERY,
+ info_readers[i].command,
+ (u8 *) battery +
+ info_readers[i].offset);
+ if (result) {
+ printk("FAIL\n");
+ break;
+ }
+ }
}
return result;
}
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