Hi Grygorii,
On 13 July 2017 10:27, Phil Edworthy wrote:
> On 12 July 2017 18:32, Grygorii Strashko wrote:
> > On 07/12/2017 08:55 AM, Phil Edworthy wrote:
> > > Hi,
> > >
> > > I'm new to rt-linux, so please forgive me if I ask some dumb questions.
> > > I have searched for a while, but not found what I am looking for.
> > >
> > > I'm trying out the rt-linux patches (v4.9.35) on an out-of-tree BSP
> > > for a new ARM Cortex A7 device. When I tried cyclictest, it complained
> > > that I don't have High Resolution timers, so I checked and sure enough
> > > /proc/timer_list showed the timer resolution is 10ms. I've checked my
> > > kernel config and I have enabled hrtimers.
> > >
> > > This device uses the ARM architected timer
> (CONFIG_ARM_ARCH_TIMER)
> > > running at a lowly 6.25MHz.
> > >
> > > So, how can I tell if a driver is supposed to support hrtimers?
> > > If the ARM architected timer driver does support hrtimers, what could
> > > stop them being used?
> >
> >
> > Most probably you do not have at least one tick_broadcast timer enabled.
> > See:
> > tick_check_oneshot_change()->tick_is_oneshot_available()
> Many thanks for the pointer, I didn't know where to start looking.
> You are right, tick_is_oneshot_available is returning 0 because
> in tick_broadcast_oneshot_available () the code determines that the timer
> doesn't
> have CLOCK_EVT_FEAT_ONESHOT. However, the ARM arch timer does
> enable
> that feature.
>
> So does this mean the ARM arch timer is used for something else, thus I
> cannot
> use it for an hrtimer?
I found that I had to enable another timer on the device and now I've got hrtimers!
If only one of the timers is enabled, no hrtimers.
Thanks for your help
Phil
��.n��������+%������w��{.n�����{�����ǫ���ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
