On Sun, Dec 18, 2016 at 09:35:48AM +0200, Igor Grinberg wrote: > Hi Aniroop Mathur, > > > On 12/04/16 15:05, Aniroop Mathur wrote: > > Hello Mr. Igor Grinberg > > > > On Sun, Dec 4, 2016 at 1:32 PM, Igor Grinberg <grinberg@xxxxxxxxxxxxxx> wrote: > >> Hi Aniroop Mathur, > >> > >> On 11/29/16 23:02, Aniroop Mathur wrote: > >>> Dear Mike Rapoport, Igor Grinberg, > >>> Greetings! > >>> > >>> I am Aniroop Mathur from Samsung R&D Institute, India. > >>> > >>> I have submitted one patch as below for review to Linux Open Source. > >>> The problem is that we do not have the hardware available with us to > >>> test it and we would like to test it before actually applying it. > >>> As you are the author of this driver, I am contacting you to request you > >>> provide your feedback upon this patch. > >>> > >>> Also if you have the hardware available, could you please help to > >>> test this patch on your hardware? or could you provide contact points > >>> of individuals who could support to test it? > >> > >> This touchpad and the driver was used on an old PXA270 based PDA. > >> I currently don't have those at hand to test the patch. > >> > >>> > >>> Thank you! > >>> > >>> BR, > >>> Aniroop Mathur > >>> > >>> On Tue, Nov 29, 2016 at 1:25 AM, Aniroop Mathur <a.mathur@xxxxxxxxxxx> wrote: > >>>> msleep(1~20) may not do what the caller intends, and will often sleep longer. > >>>> (~20 ms actual sleep for any value given in the 1~20ms range) > >> > >> Well, it should be at least 1ms as stated in my comment just before the define. > >> So, from the correctness perspective larger values will also do the job. > >> Additionally, since I've taken a spare 2ms, and you are making it even more > >> precise (3000us + 100us) - it will still do the job and stay correct. > >> So, there should be no issue from correctness POV. > >> > > > > Alright, Thanks! > > > >>>> This is not the desired behaviour for many cases like device resume time, > >>>> device suspend time, device enable time, retry logic, etc. > >>>> Thus, change msleep to usleep_range for precise wakeups. > >> > >> This is a human interface touchpad device, even having 20ms soft reset > >> sleep time will not impact the responsiveness for humans. > >> IMHO, there is no need for precise wakeups for this device, so I wouldn't > >> bother. > >> > > > > Well, from the point of view of device working and responsiveness for "humans", > > I agree that it is okay to sleep for 20 / 40 ms or even 100 ms. However, this > > patch is not trying to solve any such issues. This patch is only trying to make > > the process sleep for appropriate time as mentioned in the parameter and does > > not cause any harm here. I could see that this function is called during device > > resume and device probe time. So this change will improve the resume and probe > > time for this device and doing the same change in other drivers will > > contribute to > > improvement in overall kernel resume and boot time a little bit so response time > > increases a little bit. Plus, it is recommended and mentioned in kernel > > documentation to use usleep_range for delays between 1-10 ms. > > So usleep_range should serve better here. > > Explained originally here to why not use msleep for 1 - 20 ms: > > http://lkml.org/lkml/2007/8/3/250 > > I have absolutely 0 objections to this. > So, as I already have said, it will be hard for me to test it currently, but > if you want it and Dmitry wants to apply it, my ack is below. OK, it does not matter much either way, but let's apply it. > > >>>> > >>>> Signed-off-by: Aniroop Mathur <a.mathur@xxxxxxxxxxx> > > Acked-by: Igor Grinberg <grinberg@xxxxxxxxxxxxxx> Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
