On Sun, Apr 28, 2019 at 09:50:35PM +0200, Daniel Mack wrote: > On 28/4/2019 7:36 PM, Dmitry Torokhov wrote: > > On Sun, Apr 28, 2019 at 09:18:46AM +0200, Daniel Mack wrote: > >> On 23/4/2019 10:41 AM, Dmitry Torokhov wrote: > >>> On Tue, Apr 23, 2019 at 06:51:32AM +0200, Daniel Mack wrote: > >>>> Hi Dmitry, > >>>> > >>>> On 23/4/2019 5:17 AM, Dmitry Torokhov wrote: > >>>>> On Mon, Apr 22, 2019 at 10:35:40AM +0200, Daniel Mack wrote: > >>>>>> For systems in which the touch IRQ is acting as wakeup source, the interrupt > >>>>>> controller might not latch the GPIO IRQ during sleep. In such cases, the > >>>>>> interrupt will never occur again after resume, hence the touch screen > >>>>>> appears dead. > >>>>>> > >>>>>> To fix this, call into eeti_ts_read() once to read the hardware status and > >>>>>> to arm the IRQ again. > >>>>> > >>>>> Can you instead make the interrupt level-triggered? > >>>> > >>>> The hardware I'm working on doesn't support that unfortunately. > >>>> > >>>> In fact, the whole attn-gpio dance is there because of that, and the > >>>> GPIO descriptor maps to the same pin that also causes the IRQ in my case. > >>> > >>> OK, if the interrupt controller is incapable of dealing with level > >>> interrupts then we have to do what you propose. > >> > >> So you consider these patches for inclusion then? I'm just asking > >> because I can't see them in your tree yet. > > > > I was about to, but now I wonder if we need a mutex in the isr code now, > > otherwise there is a chance it will be running concurrently when we are > > resuming if interrupt does latch. > > Actually, to address that, all we need to do is call into eeti_ts_read() > before enable_irq(). See my v2. This is still a bit racy as interrupt may come after you attempted to read but before enable_irq() and then we need interrupt replaying code to work reliably, which, as far as I understand, is not always the case. I suppose we need at least add a comment that we rely on replays. What kind of hardware is that? Is there no chance of making interrupt controller handle level interrupts? Thanks. -- Dmitry
