[Intel-gfx] [PATCH] lib/igt_aux: make igt_wait_for_pm_status() resist the signal helper

[Daniel Vetter]

On Tue, Oct 21, 2014 at 01:52:46PM -0200, Paulo Zanoni wrote:
> 2014-10-21 13:18 GMT-02:00 Daniel Vetter <daniel at ffwll.ch>:
> > On Tue, Oct 14, 2014 at 04:12:22PM -0300, Paulo Zanoni wrote:
> >> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> >>
> >> If the signal helper is active, the usleep() calls return earlier, and
> >> we may end up returning false way before the 10s timeout, failing the
> >> subtests. This currently happens on the kms_flip RPM interruptible
> >> subtests.
> >>
> >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=78893
> >> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> >> ---
> >>  lib/igt_aux.c | 17 ++++++++++++-----
> >>  1 file changed, 12 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/lib/igt_aux.c b/lib/igt_aux.c
> >> index b32297e..01654f0 100644
> >> --- a/lib/igt_aux.c
> >> +++ b/lib/igt_aux.c
> >> @@ -42,6 +42,7 @@
> >>  #include <stdlib.h>
> >>  #include <unistd.h>
> >>  #include <sys/wait.h>
> >> +#include <sys/time.h>
> >>  #include <sys/types.h>
> >>  #include <sys/syscall.h>
> >>  #include <sys/utsname.h>
> >> @@ -502,21 +503,27 @@ enum igt_runtime_pm_status igt_get_runtime_pm_status(void)
> >>   * Waits until for the driver to switch to into the desired runtime PM status,
> >>   * with a 10 second timeout.
> >>   *
> >> + * Some subtests call this function while the signal helper is active, so we
> >> + * can't assume each usleep() call will sleep for 100ms.
> >> + *
> >>   * Returns:
> >>   * True if the desired runtime PM status was attained, false if the operation
> >>   * timed out.
> >>   */
> >>  bool igt_wait_for_pm_status(enum igt_runtime_pm_status status)
> >>  {
> >> -     int i;
> >> -     int hundred_ms = 100 * 1000, ten_s = 10 * 1000 * 1000;
> >> +     struct timeval start, end, diff;
> >>
> >> -     for (i = 0; i < ten_s; i += hundred_ms) {
> >> +     igt_assert(gettimeofday(&start, NULL) == 0);
> >> +     do {
> >>               if (igt_get_runtime_pm_status() == status)
> >>                       return true;
> >>
> >> -             usleep(hundred_ms);
> >> -     }
> >> +             usleep(100 * 1000);
> >> +
> >> +             igt_assert(gettimeofday(&end, NULL) == 0);
> >> +             timersub(&end, &start, &diff);
> >
> > Should we have a generic igt_usleep helper which is signal-robust? Just a
> > quick idea since there's probably more like these.
> 
> If we think we could use it in many places, it makes sense. I'm not
> aware yet of where we could use it.

Do a cocci patch to replace all the existing usleep with igt_usleep
extracted from here. Run it on tests/*.c.

We already have a cocci spatch in lib/igt.cocci with lots of default
refactorings like that to replace C functions with igt helpers where it
makes sense. Signed up? And even if it's just to learn a bit how
coccinelle works, that alone is awesome ;-)
-Daniel
> 
> > -Daniel
> >
> >> +     } while (diff.tv_sec < 10);
> >>
> >>       return false;
> >>  }
> >> --
> >> 1.9.1
> >>
> >> _______________________________________________
> >> Intel-gfx mailing list
> >> Intel-gfx at lists.freedesktop.org
> >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > +41 (0) 79 365 57 48 - http://blog.ffwll.ch
> 
> 
> 
> -- 
> Paulo Zanoni

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch