On Wed, May 21, 2014 at 01:01:31PM +0200, Rafael J. Wysocki wrote: > On Wednesday, May 21, 2014 01:05:11 PM Heikki Krogerus wrote: > > On Tue, May 20, 2014 at 11:33:09PM +0200, Rafael J. Wysocki wrote: > > > First, is the 10 ms sleep really necessary? I'd expect the AML to take care of > > > such delays (this is not a PCI device formally). > > > > Unfortunately that is not the case. There is nothing in the AML for > > this. Mika, correct me if I'm wrong. > > > > > And because this is not a PCI device formally, why is the comment talking about > > > the PCI spec? Why is PCI relevant in any way here? > > > > Under the hood the devices are still PCI devices, even if they > > formally aren't. Maybe I should point that out in the comment.. > > > > We put the sleep there because without it there was no guarantee if > > the device was properly resumed by the time the drivers resume hooks > > were called. The symptom in case of a failure was simply that the > > registers could not be written, which leads into timeouts at least in > > case of the I2C and UART and making them unusable until the next > > suspend followed by resume. > > OK, so the msleep() is functionally necessary. Instead of talking about the > PCI in the comment, which will make a casual reader think "What the heck?", > please say something like "the delay is necessary for the subsequent register > writes to succeed on <example system>". OK. Thanks, -- heikki -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
