From mboxrd@z Thu Jan 1 00:00:00 1970 From: sylvain.rochet@finsecur.com (Sylvain Rochet) Date: Fri, 19 Dec 2014 16:26:25 +0100 Subject: AT91 slow clock mode regression/fixes, improvement proposal In-Reply-To: References: <20141218203904.GA25215@gradator.net> Message-ID: <20141219152625.GA30666@gradator.net> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hello Wenyou, On Fri, Dec 19, 2014 at 02:50:04AM +0000, Yang, Wenyou wrote: > > > > Is actually jumping to wait_pllblock before enabling PLLB instead of skipping UTMI > > PLL. Unfortunately the compiler does not warn about that. > > Thanks. I will check it Fixed in proposed patch (UPLL code removed). > > Furthermore, it looks like MCKRDY_TIMEOUT set to 1000 is not enough, my board > > crashes in about 1 wake up to 10 with this value and works perfectly > > fine with 4000. > > I also encountered this issue. Fixed in proposed patch, since we don't timeout anymore. > Moreover the Main Crystal Oscillator Startup Time seems not enough > too, not sure, I am confirming it. This is OK for me, CKGR_MOR.MOSCXTST is set to 8: (1/32768)*8*8 = 1.95 ms I checked with a scope on XTAL of the AT91SAM9G35-CM module, 2 ms is about twice enough waiting time. > > Therefore I am also proposing to remove all the timeout. > > Good idea, but I still worry the deadlock without timeout. Maybe > increasing timeout is better. This is just a test request patch, I am first trying without timeout to get some feedback. It works well for me, at least, but this isn't convicing myself enough :-) > > By the way, I don't know for other AT91 boards (or without DT, or > > something else), but the UTMI PLL suspend/resume seem unnecessary for > > me, the USB driver is already disabling the USB PLL when suspending, > > could you confirm ? > Yes, I agree. Removed. > Remove disabling the PLLB code as well. Done, but my SoC don't have a PLLB, so I can't check myself, could you check if "AT91: PM - Suspend-to-RAM with PLL B running" does not fire on PLL B enabled board ? Regards, Sylvain