On Wed, 24 Oct 2012, Rob Herring wrote: > On 10/24/2012 11:44 AM, Alan Stern wrote: > > On Wed, 24 Oct 2012, Stephen Warren wrote: > > > >> We should absolutely avoid Linux-specific properties where possible. > >> > >> That said, what Linux-specific properties are you talking about? The > >> properties discussed here (has-synopsys-hc-bug, no-io-watchdog, has-tt) > >> are all purely a description of HW, aren't they. > > > > "has-tt" is definitely a description of the HW. > > Can you spell out tt. It stands for Transaction Translator. The acronym is a standard one, used in the USB specs. > > "has-synopsys-hc-bug" is too, although determining whether or not it > > should apply to a particular controller might be difficult. I'm > > inclined not to include it among the properties. > > What happens when there are 2 synopsys hc bugs? Something more specific > about what the bug is would be better. We will leave it out. > > "no-io-watchdog" is not the greatest name. It describes to controllers > > that always do generate IRQs for I/O events when they are supposed to > > (and hence the driver doesn't need to set up a watchdog timer to detect > > I/O completions that didn't generate an IRQ). So while the concept is > > HW-specific, the name refers to a driver implementation issue. A > > better name might be something like "reliable-IRQs". Again, it's not > > such an easy thing to test for. Almost all the existing drivers leave > > it unset. > > Shouldn't the default be reliable irqs? What about "unreliable-irqs"? I don't know why the default was set the way it was. That was before my time as EHCI maintainer. Right now only a few EHCI drivers claim to have reliable IRQs. Avoiding the watchdog timer is a fairly minor optimization in any case. It fires only once every 100 ms, and only while I/O is in progress. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
