[Intel-gfx] [PATCH igt 1/2] lib: Attempt to load the module for a missing device

[Petri Latvala]

On Tue, Nov 14, 2017 at 01:56:22PM +0000, Chris Wilson wrote:
> Quoting Chris Wilson (2017-11-14 13:18:44)
> > If we asked to open a particular chipset and we find no matching device,
> > try again after attempting to load its module. Previously we only did
> > this for vgem, which is not automatically probed during boot, but if we
> > want to leave the module unloaded we have to try harder when we need the
> > device.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > ---
> >  lib/drmtest.c | 68 +++++++++++++++++++++++++++++++++++++++++++----------------
> >  1 file changed, 50 insertions(+), 18 deletions(-)
> > 
> > diff --git a/lib/drmtest.c b/lib/drmtest.c
> > index e6bdbc35..3a2a6343 100644
> > --- a/lib/drmtest.c
> > +++ b/lib/drmtest.c
> > @@ -235,20 +235,14 @@ static int modprobe(const char *driver)
> >         return igt_kmod_load(driver, "");
> >  }
> >  
> > -/**
> > - * __drm_open_driver:
> > - * @chipset: OR'd flags for each chipset to search, eg. #DRIVER_INTEL
> > - *
> > - * Open the first DRM device we can find, searching up to 16 device nodes
> > - *
> > - * Returns:
> > - * An open DRM fd or -1 on error
> > - */
> > -int __drm_open_driver(int chipset)
> > +static void modprobe_i915(const char *name)
> >  {
> > -       if (chipset & DRIVER_VGEM)
> > -               modprobe("vgem");
> > +       /* When loading i915, we also want to load snd-hda et al */
> > +       igt_i915_driver_load(NULL);
> > +}
> >  
> > +static int __open_device(unsigned int chipset)
> > +{
> >         for (int i = 0; i < 16; i++) {
> >                 char name[80];
> >                 int fd;
> > @@ -262,16 +256,13 @@ int __drm_open_driver(int chipset)
> >                     has_known_intel_chipset(fd))
> >                         return fd;
> >  
> > -               if (chipset & DRIVER_VC4 &&
> > -                   is_vc4_device(fd))
> > +               if (chipset & DRIVER_VC4 && is_vc4_device(fd))
> >                         return fd;
> >  
> > -               if (chipset & DRIVER_VGEM &&
> > -                   is_vgem_device(fd))
> > +               if (chipset & DRIVER_VGEM && is_vgem_device(fd))
> >                         return fd;
> >  
> > -               if (chipset & DRIVER_VIRTIO &&
> > -                   is_virtio_device(fd))
> > +               if (chipset & DRIVER_VIRTIO && is_virtio_device(fd))
> >                         return fd;
> >  
> >                 if (chipset & DRIVER_AMDGPU && is_amd_device(fd))
> > @@ -287,6 +278,47 @@ int __drm_open_driver(int chipset)
> >         return -1;
> >  }
> >  
> > +/**
> > + * __drm_open_driver:
> > + * @chipset: OR'd flags for each chipset to search, eg. #DRIVER_INTEL
> > + *
> > + * Open the first DRM device we can find, searching up to 16 device nodes
> > + *
> > + * Returns:
> > + * An open DRM fd or -1 on error
> > + */
> > +int __drm_open_driver(int chipset)
> > +{
> > +       static const struct {
> > +               unsigned int bit;
> > +               const char *module;
> > +               void (*modprobe)(const char *name);
> > +       } modules[] = {
> > +               { DRIVER_AMDGPU, "amdgpu" },
> > +               { DRIVER_INTEL, "i915", modprobe_i915 },
> > +               { DRIVER_VC4, "vc4" },
> > +               { DRIVER_VGEM, "vgem" },
> > +               { DRIVER_VIRTIO, "virtio-gpu" },
> > +               {}
> > +       }, *m;
> > +       int fd;
> > +
> > +       fd = __open_device(chipset);
> > +       if (fd != -1)
> > +               return fd;
> > +
> > +       for (m = modules; m->module; m++) {
> > +               if (chipset & (1ul << m->bit)) {
> 
> Eek, m->bit is already a bit and not a shift.
> 
> Still puzzled where the device went between tests though, no sign of it
> being unloaded.


I don't see any signs of it being loaded in the first
place. Assuming I'm reading right and this is the correct line to look
for (from the base run):


<6>[  265.406984] [drm] Initialized vgem 1.0.0 20120112 for virtual device on minor 1



-- 
Petri Latvala