Felipe, > -----Original Message----- > From: Balbi, Felipe > Sent: Thursday, April 02, 2015 2:44 PM > To: Liu, Bin > Cc: Balbi, Felipe; linux-usb@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v2] usb: musb: only set test mode once > > On Thu, Apr 02, 2015 at 01:48:35PM -0500, Liu, Bin wrote: > > Felipe, > > > > > -----Original Message----- > > > From: Balbi, Felipe > > > Sent: Thursday, April 02, 2015 1:22 PM > > > To: Liu, Bin > > > Cc: linux-usb@xxxxxxxxxxxxxxx; Balbi, Felipe > > > Subject: Re: [PATCH v2] usb: musb: only set test mode once > > > > > > On Thu, Apr 02, 2015 at 11:44:30AM -0500, Liu, Bin wrote: > > > > Felipe, > > > > > > > > > -----Original Message----- > > > > > From: Liu, Bin > > > > > Sent: Tuesday, March 24, 2015 3:09 PM > > > > > To: linux-usb@xxxxxxxxxxxxxxx > > > > > Cc: Balbi, Felipe; Liu, Bin > > > > > Subject: [PATCH v2] usb: musb: only set test mode once > > > > > > > > > > The MUSB test mode register can only be set once, otherwise the > > > > > result is undefined. > > > > > > > > > > This prevents the debugfs testmode entry to set the register > > > > > more than once which causes test failure. > > > > > > > > > > Signed-off-by: Bin Liu <b-liu@xxxxxx> > > > > > > > > I see you have not picked up this patch yet. Can you please hold > > > > on it? > > > > > > > > I noticed only the USB2.0 Specs mentioned about USB reset to exit > > > > test mode, but not in the MUSB data manual. > > > > > > > > I am guessing running multiple 'test packet' command causing > > > > incorrect test packets is due to the driver loading the test > > > > packets into EP0 FIFO multiple times. I simply masked this then > > > > the analyzer trace shows the test packets are correct even after ran 'test > packet' > > > > command multiple times. > > > > > > > > I will have to hook up a scope to measure the signal to ensure the > > > > DP/DM signals are still correct after run each test mode command > > > > multiple times for MUSB. If so, then the patch we need is to > > > > ensure not loading the test packet to FIFO multiple times. > > > > > > MUSB still needs to obey what USB 2.0 specification says and if it > > > says we must reset, then we must reset ;-) > > > > This is right. But the Specs only says the hub reset is required when > > *exit* test mode, it did not say a reset is required when switching > > between test modes. > > to enter a new test mode, you must first exit the previous one ;-) Yeah, you are right. > > > I really don't care about reset or not, it is just about board reboot, > > not a big deal. The only thing I want to do is prevent the *** user > > using the current driver loading test packets to FIFO multiple times > > which breaks the test. > > You don't need to reboot the board at all. When USB spec says 'reset', it's > referring to a USB bus reset. See if my device-reset tool helps you out [1] > > [1] https://gitorious.org/usb/usb- > tools/source/373b417a9f0ded25312d0626486f6e7a2d660c32:device-reset.c This is to reset the bus, not the controller right? For the MUSB case, the controller itself needs reset, no device/hub is connected on the bus. Regards, -Bin. > > -- > balbi -- 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
