On Mon, Dec 12, 2011 at 9:12 PM, Felipe Balbi <balbi@xxxxxx> wrote: > On Mon, Dec 12, 2011 at 08:30:49PM +0200, Felipe Contreras wrote: >> The short version is this: either we revert this patch[1], or we apply >> this patch series[2], as well as its essential fixes[3]. >> >> The long version is this. There's a synchronization issue with the >> current keypad driver and twl core; the irq is marked as handled even >> though the thread that is supposed to handle it hasn't run yet, and >> since it's clear-on-read, and it hasn't been read, it's detected >> again, so they keypad driver receives two interrupt callbacks instead >> of one, and in the second one reads nothing from the i2c register, so >> a key release is assumed. This makes key-presses as simple as shift+a >> impossible. >> >> In other words, it's totally unreliable. This might not be isolated to >> the keypard driver, but other "nested" interrupts from twl core that >> started using request_threaded_irq prematurely (before it was >> supported by the twl core). But at least I haven't tried those. >> >> This patch was applied on 2.6.33, which means all versions before 3.2 >> are affected, including 3.1. >> >> What do you think about fixing this on stable kernels? > > I believe Samuel has already applied those to the MFD tree. Yeap, I think Linus' tree is going to be fine (3.2), but I'm trying to find out what to do with previous kernels: as in, what should be done for stable trees. > The funny part is that those patches were pending on linux-omap for over 2 > months I have refreshed them over and over again and asked for help from > other people to test. You mean these patches? [1] There's nothing wrong with pushing them forward, but I'm actually talking about this one [2]. > Everything went smooth on my simple beagle board with no keypad and I > couldn't see any issues, unfortunately. That's because you didn't get a single interrupt. You could have added a BUG() on handle_twl4030_pih() and you still wouldn't have noticed anything. > Still, 2 months is a whole lot of time to NAK a patch, but nobody said > anything so, of course, It's actually almost 2 years :) > Samuel assumed it was ok and, like I said above, it worked for my simple GPIO > usecase with beagleboard. Well, for 3.2 I think the situation is fine, but that's not what I'm talking about. About your GPIO tests, are you sure you got the interrupts through twl4030 irq handling? Cheers. [1] http://article.gmane.org/gmane.linux.ports.arm.omap/59958 [2] http://article.gmane.org/gmane.linux.kernel/932255 -- Felipe Contreras -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
