On 12/02/2013 04:03 PM, Sebastian Andrzej Siewior wrote: > On 12/02/2013 02:44 PM, Roger Quadros wrote: >> "Errata id: i660 >> DESCRIPTION >> In the following configuration : >> • USBHOST module is set to smart-idle mode >> • PRCM asserts idle_req to the USBHOST module. (This typically happens when the system is going to >> a low power mode : all ports have been suspended, the master part of the USBHOST module has >> entered the standby state, and SW has cut the functional clocks.) >> • an USBHOST interrupt occurs before the module is able to answer idle_ack, typically a remote wakeup >> IRQ. >> Then the USB HOST module will enter a deadlock situation where it is no more accessible nor functional. >> The only way to recover will be to perform a software reset of the module. >> >> WORKAROUND >> The best workaround consists in switching the module to force idle mode right before cutting the >> module's FCLK. >> • the bus has reached the suspend state. >> • write SYSCONFIG:Idlemode= ForceIdle and read it back to ensure the write has been taken into >> account in case of posted writes. >> • cut the FCLK >> • Idle_req will be asserted and idle_ack answered within one L3 clock cycle. >> Upon resume or remote wakeup, switch back the module to smart-idle. >> This workaround reduces the failure window to only one L3 clock cycle. The probability for an interrupt to >> fire at this exact time is considered extremely low, and the case has never been hit on board." >> >> Based on this, I don't see anything wrong in Resetting the module at probe or at boot. > > If u-boot configured USB into something not smart-idle and the reset > would bring it back then the reset should remain. > If you could tell hwmod not use smart-idle nor smart-standby and you > make sure that the suspend code manually puts the device into suspend > via forceidle then I think could get rid of the "do-not-reset-thingy". > We are already telling hwmod to not use smart-idle or smart-standby. So the device is always put in no-idle,no-standby during resume and force-idle,force-standby during suspend. I'll send a new patch to remove "do-not-reset" flag from hwmod data and then we don't need this patch. cheers, -roger -- 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
