Re: [PATCH i-g-t 01/39] lib/drmtest: Add VKMS as a known driver type

[Louis Chauvet <louis.chauvet@bootlin.com>]

Le 18/02/2025 à 17:49, José Expósito a écrit :
> As we are going to add VKMS specific tests, allow to check if it is
> available.
> 
> Co-developed-by: Jim Shargo <jshargo@chromium.org>
> Signed-off-by: Jim Shargo <jshargo@chromium.org>
> Co-developed-by: Marius Vlad <marius.vlad@collabora.com>
> Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
> Signed-off-by: José Expósito <jose.exposito89@gmail.com>
> ---
>   lib/drmtest.c | 18 ++++++++++++++++++
>   lib/drmtest.h |  8 ++++++--
>   2 files changed, 24 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/drmtest.c b/lib/drmtest.c
> index 436b6de78..2cc6e0c29 100644
> --- a/lib/drmtest.c
> +++ b/lib/drmtest.c
> @@ -971,3 +971,21 @@ void igt_require_xe(int fd)
>   {
>   	igt_require(is_xe_device(fd));
>   }
> +
> +void igt_require_vkms(void)
> +{
> +	/*
> +	 * Since VKMS can create and destroy virtual drivers at will, instead
> +	 * look to make sure the driver is installed.
> +	 */
> +	struct stat s = {};
> +	int ret;
> +	const char *vkms_module_dir = "/sys/module/vkms";
> +
> +	ret = stat(vkms_module_dir, &s);
> +
> +	igt_require_f(ret == 0, "VKMS stat of %s returned %d (%s)\n",
> +		      vkms_module_dir, ret, strerror(ret));
> +	igt_require_f(S_ISDIR(s.st_mode),
> +		      "VKMS stat of %s was not a directory\n", vkms_module_dir);
> +}
> diff --git a/lib/drmtest.h b/lib/drmtest.h
> index 27e5a18e2..1b57e49ec 100644
> --- a/lib/drmtest.h
> +++ b/lib/drmtest.h
> @@ -54,15 +54,18 @@ int __get_drm_device_name(int fd, char *name, int name_size);
>   #define DRIVER_PANFROST	(1 << 5)
>   #define DRIVER_MSM	(1 << 6)
>   #define DRIVER_XE	(1 << 7)
> -#define DRIVER_VMWGFX   (1 << 8)
> +#define DRIVER_VKMS	(1 << 8)
> +#define DRIVER_VMWGFX	(1 << 9)

Is it normal to change the DRIVER_VMWGFX value?

I also found the `module` list in drmtest.c that use this value, I think 
this list is used to do the proper `modprobe` during a open_driver().

Maybe you can use it, so you will be able to do:

	drm_load_module(DRIVER_VKMS); // (If I understand correctly, this fails 
silently)
	igt_require_vkms();

And future tests requiring a vkms device will be able to do:

	open_driver(DRIVER_VKMS);

>   
>   /*
>    * Exclude DRVER_VGEM from DRIVER_ANY since if you run on a system
>    * with vgem as well as a supported driver, you can end up with a
>    * near-100% skip rate if you don't explicitly specify the device,
>    * depending on device-load ordering.
> + *
> + * Exclude VKMS to prefer hardware drivers.
>    */
> -#define DRIVER_ANY 	~(DRIVER_VGEM)
> +#define DRIVER_ANY	~(DRIVER_VGEM | DRIVER_VKMS)
>   
>   /*
>    * Compile friendly enum for i915/xe.
> @@ -135,6 +138,7 @@ void igt_require_i915(int fd);
>   void igt_require_nouveau(int fd);
>   void igt_require_vc4(int fd);
>   void igt_require_xe(int fd);
> +void igt_require_vkms(void);
>   
>   bool is_amdgpu_device(int fd);
>   bool is_i915_device(int fd);

-- 
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com