Hi, On Tue, May 01, 2018 at 08:48:11AM -0500, Bin Liu wrote: > On Fri, Apr 27, 2018 at 03:00:05PM +0200, Daniel Glöckner wrote: > > It has been observed that writing 0xF2 to the power register while it > > reads as 0xF4 results in the register having the value 0xF0, i.e. clearing > > RESUME and setting SUSPENDM in one go does not work. It might also violate > > the USB spec to transition directly from resume to suspend, especially > > when not taking T_DRSMDN into account. But this is what happens when a > > remote wakeup occurs between SetPortFeature USB_PORT_FEAT_SUSPEND on the > > root hub and musb_bus_suspend being called. > > > > This commit returns -EBUSY when musb_bus_suspend is called while remote > > wakeup is signalled and thus avoids to reset the RESUME bit. Remember that > > resume can be signalled only when the bus was already suspended, so it is > > safe to skip the following steps even when musb_hub_control ignores the > > what do you mean by "skip the following steps"? Setting USB_PORT_STAT_SUSPEND in musb->port1_status, changing musb->xceiv->otg->state, setting musb->is_active, etc. > > error returned by musb_port_suspend. > > > > The resume part of musb_port_suspend is modified to also accept a pending > > remote wakeup, to bring it to the end after T_DRSMDN has passed. > > Can you please explain more here? I am not sure when musb_port_suspend() > is involved in resume by remote wakeup, and what case is a 'pending' > remote wakeup? With 'pending' I was referring to the situation when MUSB_POWER_RESUME has been set by the controller in the power register as a result of of a detected remote wakeup. I see... finish_resume_work is already scheduled by musb_stage0_irq. So the condition of the if statement probably does not need to be changed. I'll test without that part and make a v2 patch if it works. Btw., do you know why that 10000 iterations while loop is needed in musb_port_suspend to pass the OTG Protocol Test as indicated by the comment? Best regards, Daniel -- Dipl.-Math. Daniel Glöckner, emlix GmbH, http://www.emlix.com Fon +49 551 30664-0, Fax +49 551 30664-11, Gothaer Platz 3, 37083 Göttingen, Germany Sitz der Gesellschaft: Göttingen, Amtsgericht Göttingen HR B 3160 Geschäftsführung: Heike Jordan, Dr. Uwe Kracke Ust-IdNr.: DE 205 198 055 emlix - your embedded linux partner -- 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
