Re: [PATCH v2] HID: i2c-hid: Fix suspend/resume when already runtime suspended

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Thu, Mar 12, 2015 at 11:10:14AM +0200, Mika Westerberg wrote:
> On Wed, Mar 11, 2015 at 08:06:47AM -0700, Doug Anderson wrote:
> > Mika,
> > 
> > On Wed, Mar 11, 2015 at 4:20 AM, Mika Westerberg
> > <mika.westerberg@linux.intel.com> wrote:
> > > On Tue, Mar 10, 2015 at 09:12:36AM -0700, Doug Anderson wrote:
> > >> Thanks for testing!  Can you do a "dump_stack()" here?  I'm curious
> > >> why it's deciding to runtime resume.  Maybe something changed between
> > >> 3.14 and ToT?
> > >
> > > Here you go:
> > >
> > > [   26.711737] i2c_hid i2c-ATML1000:00: PM: i2c-hid runtime resume
> > > [   26.711754] CPU: 3 PID: 123 Comm: sh Not tainted 4.0.0-rc3+ #6
> > > [   26.711775]  ffff88007604c600 ffff88007ba77ae8 ffffffff8183966e 0000000080000000
> > > [   26.711791]  ffff88017a83a020 ffff88007ba77b08 ffffffff816a0759 ffff88017a83a020
> > > [   26.711804]  ffff88017a83a0ce ffff88007ba77b18 ffffffff814ba3ee ffff88007ba77b38
> > > [   26.711807] Call Trace:
> > > [   26.711835]  [<ffffffff8183966e>] dump_stack+0x4f/0x7b
> > > [   26.711852]  [<ffffffff816a0759>] i2c_hid_runtime_resume+0x29/0x50
> > > [   26.711866]  [<ffffffff814ba3ee>] pm_generic_runtime_resume+0x2e/0x40
> > > [   26.711880]  [<ffffffff81412b15>] acpi_subsys_runtime_resume+0x1f/0x23
> > > [   26.711892]  [<ffffffff814bbeb6>] __rpm_callback+0x36/0x90
> > > [   26.711902]  [<ffffffff814bbf36>] rpm_callback+0x26/0xa0
> > > [   26.711914]  [<ffffffff814bd286>] rpm_resume+0x496/0x670
> > > [   26.711928]  [<ffffffff814bd4a0>] __pm_runtime_resume+0x40/0x60
> > > [   26.711940]  [<ffffffff81412500>] ? acpi_subsys_complete+0x1e/0x1e
> > > [   26.711951]  [<ffffffff81412515>] acpi_subsys_suspend+0x15/0x21
> > >
> > > It's the ACPI power domain that runtime resumes the device before it
> > > suspends it for system sleep.
> > 
> > OK, that explains the difference in behavior for me.  I'm on an ARM
> > board that has no ACPI, so there's no ACPI layer to runtime resume the
> > device.
> 
> That's interesting. So you have an ARM device with i2c-hid compatible
> device connected to it? Out of curiousity, do you use DT or some
> platform board file to configure the thing?
> 
> > At least it sounds like you confirmed that my patch doesn't break your
> > use case, which is good.
> 
> I actually didn't have your patch applied yet. I just wanted to verify
> that the existing code works.
> 
> Let me know and I'll run the same test with your patch applied.

I did try with the patch applied and suspend/resume worked just fine.