On Tue, May 27, 2014 at 09:35:21PM -0700, Bing Zhao wrote: > Hi James, > > > > > We use a GPIO to wake from WLAN. > > > > > > This doesn't match the gpio parameter configured in hscfg command > > > 0xe5. > > > > You're right, and I'm quite wrong. Sorry about that. I misread our > > code. > > > > Correction, we use SDIO to wake from WLAN. > > > > We set gap to 0xff, which we think is a special value that means the > > device will wait for the host to acknowledge before sending data to > > the host. > > Yes, gap=0xff should be used. Actually I also have the patch to set > gap to 0xff queued in my local tree. I will send it upstream. Thanks. Today I have been testing with gap 50ms and no longer able to reproduce the "mmc0: Timeout waiting for hardware interrupt." problem. > > Looking through history of development, we thought that this would > > avoid a race condition, where the host starts to suspend, configures > > the device for host sleep, but the device may wake in the time before > > the host suspends. > > > > We don't see this "mmc0: Timeout waiting for hardware interrupt." > > problem unless we use WPA2. It does not reproduce on an open access > > point. > > With WPA2 enabled, does the "mmc0 timeout" happen in every suspend > attempt? No, it is rare, of the order of one in every 6000 attempts, and depends on the timing of arriving packets. Our reproducer uses a ping ramp, with interval varying from 0.1 to 0.9 seconds with 50ms increment, and this brings the problem frequency down to about one in 200 attempts. The OLPC XO-4 by default tries to suspend automatically when user is idle, which is why we notice the problem. -- James Cameron http://quozl.linux.org.au/ -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
