> On 21 Dec 2017, at 7:43 PM, Daniel Drake <dr...@endlessm.com> wrote: > > On Wed, Dec 20, 2017 at 6:53 PM, Brian Norris <briannor...@chromium.org> > wrote: >> >> On Wed, Dec 20, 2017 at 07:00:07PM +0800, Kai-Heng Feng wrote: >>> This commit causes a regression on some QCA ROME chips. The USB device >>> reset happens in btusb_open(), hence firmware loading gets interrupted. >> >> Oh, did you really confirm that's the root of the problem? I was only >> hypothesizing, with some informed observation and code review; but I >> didn't fully convince myself. If so, that's interesting. > > I have the same doubt. Can you explain how/why firmware uploading and > btusb_open() overlap, and how this is avoided with your patch?
QCA ROME chip uploads its firmware inside btusb_open(). The behavior is like below: - btusb_probe() - btusb_open() - btusb_suspend(), reset_resume gets set. - btusb_open() again, hub resets the device, then the issue happens. I didn’t dig really deep for the issue, I simply tried usb core quirks, it reset the USB device before btusb_probe(). It might be that using the USB quirk only papers over the real issue. > If they do overlap, is that not a bug in the stack that should be fixed > instead? > If the fix belongs in btusb and this BTUSB_RESET_RESUME thing really > is problematic, should it be totally removed instead? I think so. That’s why I need some insight from the original patch author. Kai-Heng > > Daniel -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
