On Tue, Jan 13, 2009 at 09:29:18AM +0000, Daniel Silverstone wrote: > On Mon, 2009-01-12 at 21:33 -0800, Dmitry Torokhov wrote: > > > > > + /* Always service the USB devices irq not just when the input device is > > > > > + * open. > > > > > + */ > > > > > + int irq_always; > > > > Why is this needed? > > > Some devices (E.g. specifically this one) expect their interrupt > > > endpoints to always be serviced. In this case, the device has an > > > on-board watchdog and will reboot (disconnect and reconnecting to the > > > USB) if it is not serviced in a timely fashion. > > So what happens if driver was unloaded or there was no driver loaded at > > all? Is this device constantly connecting and reconnecting? > > As I understand it; yes. (Some bits of hardware really are hideous > things) Indeed if the driver fails to load quickly enough, the device > might disconnect/reconnect before the driver can get hold of it. > Geez... you sure it wasn't just broken device/batch? > > > > > + dev->touch = 1; > > > > > + dev->press = 1; > > > > Since the device does not report real pressure readings don't try to > > > > fake it, reporting touch is enough. > > > I believe that this is because some userland libraries, particularly > > > tslib, require the pressure reading in order to believe the device is > > > functioning usefully. Specifically, consider plugins/input-raw of > > > tslib's source package which uses pressure rather than touch. > > Yes, I am aware of TSLIB case and I am telling everyone who submits > > touchscreen drivers that they need to fix it. The policy is that > > kernel should not generate fake events but present as accurate state > > of hardware as possible. > > Unfortunately it's often harder to get people to change their userland > than their kernel. It seems a pity to make the driver less useful during > any longer-term effort to fix TSLIB. If acceptance of this patch is > predicated on removing that then I guess we'll have to discuss it > amongst ourselves and try and work out what we'd rather do. Is removing > the fake pressure report a requirement or a would-like? > I just checked TSLIB and the change to recognize devices that do not report pressure was applied 2 months ago so everything should work fine now. I do not think that we need to implement workarounds in newly added drivers just because users are not willing to upgrade their TSLIB installation. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
