[igt-dev] [PATCH] [PATCH i-g-t]lib/sw_sync:Fixing modprobe for sw_sync to return if not supported

[Melkaveri, Arjun]

On Fri, Jul 03, 2020 at 12:04:49PM +0100, Chris Wilson wrote:
> Quoting Arjun Melkaveri (2020-07-03 11:33:52)
> > Few tests that use "igt_require_sw_sync" , would not skip or assert the
> > test if it fails to load sw_sync module.
> > 
> > Mentioned error is seen and test continues executing .
> > "igt_kmod-DEBUG: Unknown symbol in module sw_sync or unknown parameter"
> > 
> > igt_require for modprobe in this file would skip the test if it fails
> > to load the module.
> 
> Which then fails when it is builtin.
> 
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> > Signed-off-by: Arjun Melkaveri <arjun.melkaveri at intel.com>
> > ---
> >  lib/sw_sync.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> > 
> > diff --git a/lib/sw_sync.c b/lib/sw_sync.c
> > index e860a2c1..ed8375ca 100644
> > --- a/lib/sw_sync.c
> > +++ b/lib/sw_sync.c
> > @@ -228,16 +228,17 @@ int sync_fence_status(int fence)
> >         return info.status;
> >  }
> >  
> > -static void modprobe(const char *driver)
> > +static int modprobe(const char *driver)
> >  {
> > -       igt_kmod_load(driver, NULL);
> > +       return igt_kmod_load(driver, NULL);
> >  }
> >  
> >  static bool kernel_has_sw_sync(void)
> >  {
> >         char buf[128];
> >  
> > -       modprobe("sw_sync");
> > +       /* Make sure our Kernel supports sw_sync and the module is loaded. */
> > +       igt_require(modprobe("sw_sync") == 0);
> >  
> >         return kernel_sw_sync_path(buf, sizeof(buf));
> 
> It's the return from this function that needs to be checked, and indeed
> is: igt_require_sw_sync().
> -Chris
Test is able to find the path, but throws "Unknown symbol in module
sw_sync or unknown parameter" error from modprobe-> igt_kmod_load .
execision continues as Return value from igt_kmod_load is not been checked .
I put that check only to make sure that modprob is success . 

-Arjun