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

[Chris Wilson]

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.
-Chris