On 03/19/2018 02:56 PM, Vladimir Zapolskiy wrote: > On 03/19/2018 03:48 PM, Marek Vasut wrote: >> On 03/19/2018 02:43 PM, Vladimir Zapolskiy wrote: >>> On 03/19/2018 12:56 PM, Marek Vasut wrote: >>>> On 03/19/2018 11:53 AM, Geert Uytterhoeven wrote: >>>>> Hi Marek, >>>>> >>>>> On Mon, Mar 19, 2018 at 10:53 AM, Marek Vasut <marek.vasut@xxxxxxxxx> wrote: >>>>>> On 03/19/2018 09:38 AM, Simon Horman wrote: >>>>>>> On Sun, Mar 18, 2018 at 11:52:52AM +0100, Marek Vasut wrote: >>>>>>>> The data link active signal usually takes ~20 uSec to be asserted, >>>>>>>> poll the bit more often to avoid useless delays in this function. >>>>>>>> >>>>>>>> Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxx> >>>>>>>> Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> >>>>>>>> Cc: Phil Edworthy <phil.edworthy@xxxxxxxxxxx> >>>>>>>> Cc: Simon Horman <horms+renesas@xxxxxxxxxxxx> >>>>>>>> Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx> >>>>>>>> Cc: linux-renesas-soc@xxxxxxxxxxxxxxx >>>>>>> >>>>>>> Unless my eyes deceive me this seems to be quite a lot (100x) more often, >>>>>>> but so be it. >>>>>> >>>>>> It's just a higher frequency to avoid slowdown when bringing the link up. >>>>> >>>>> No it isn't: you replaced a sleep by a delay, thus making it blocking. >>>> >>>> For much shorter period of time. >>>> >>>>> So this can spin for up to 50 ms (+ overhead)? >>>> >>>> That's what it did before too , it used msleep and now it uses udelay. >>>> >>> >>> msleep() does not spin, it reschedules the process. >>> >>> Instead to find a balance you may want to play with usleep_range(). >> >> Which does not work in atomic context, which will be needed when using >> this function in suspend/resume later on. >> > > IIRC suspend/resume are never executed in atomic context, and runtime > suspend/resume are invoked in atomic context only if pm_runtime_irq_safe() > is called (just a few drivers in vanilla uses it at the moment). > > Nevertheless, the commit message does not say that the change is needed > for future suspend/resume add-on. Well, then drop this patch for now, I'll resubmit it later with the suspend/resume series. I presume 2/2 can go in though, so I don't have to resubmit it over and over again. -- Best regards, Marek Vasut
