On Mon, Jul 29, 2019 at 10:11:51AM -0500, Aaron Sierra wrote: > ----- Original Message ----- > > From: "Andy Shevchenko" <andriy.shevchenko@xxxxxxxxxxxxxxx> > > To: "Aaron Sierra" <asierra@xxxxxxxxxxx> > > Sent: Monday, July 29, 2019 7:00:59 AM > > On Sun, Jul 28, 2019 at 05:12:09PM -0500, Aaron Sierra wrote: > >> ----- Original Message ----- > >> > From: "Andy Shevchenko" <andriy.shevchenko@xxxxxxxxxxxxxxx> > >> > Sent: Sunday, July 21, 2019 9:26:59 AM > > I'm not so familiar with the hardware, will it not give any side-effects? > > Clearing INT0 prevents PCI interrupts from getting stuck, either on in the > case of level-sensitive interrupts (e.g. INTx) or apparently-off in the case > of edge-sensitive interrupts (e.g. MSI), due to sources outside of the > typical 8250 serial port scope. Interrupts due to port wake-up after > idle/sleep are the best documented problem case. > > I do not think it was ever ideal that each port cleared INT0 multiple times > during startup. Clearing INT0 after we register the interrupt handler > responsible for INT0 should be enough to ensure that we won't run into either > case. The handler runs even if no ports are "up", so individual ports don't > have to worry so much. > > My original suggestion was incomplete in its handling of PCI device > suspense/resume. A complete solution would read INT0 in exar_resume(), too. Thanks for explanation, perhaps you can prepare a follow up on top on my series. > > So, I prefer do this in a separate change, so we may see how it goes. > > I think it's fine to defer this change to a later patch, but I would like to > see the commit message body for the current patch be more explicit that it is > not moving *all* Exar quirks. I wonder, too, if these should be broken > down into separate patches for the three classes of quirks that you move: > > * autoconfig_16550a() > * serial8250_do_[get|set]_divisor() > * serial8250_set_sleep() Yes, this will be better in case if some problems would be discovered in the future, hope none. So, let me split this to three, and then, if you have a chance to provide the one described above, I will chain it to the series. -- With Best Regards, Andy Shevchenko
