[igt-dev] [PATCH i-g-t v3] Add support for forcing a specific driver

[Rodrigo Siqueira]

Hi,

I tested the feature and everything worked as expected.

Thanks

Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>

On 12/18, Petri Latvala wrote:
> This commit adds a new option for forcing the use of a specific driver
> indicated via an environment variable.
> 
> v2 (Petri):
>  - Use an environment variable instead of command line
>  - Refactor the loop in __open_device
>  - Don't try to load kernel modules
> 
> v3 (Petri):
>  - Rebase and adjust to the driver loading changes
> 
> Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>
> Signed-off-by: Petri Latvala <petri.latvala at intel.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
> Cc: gustavo at padovan.org
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch> #v2
> ---
>  lib/drmtest.c  | 32 ++++++++++++++++++++++++++++++++
>  lib/drmtest.h  |  2 ++
>  lib/igt_core.c |  5 +++++
>  3 files changed, 39 insertions(+)
> 
> diff --git a/lib/drmtest.c b/lib/drmtest.c
> index d2aa1c19..35914c50 100644
> --- a/lib/drmtest.c
> +++ b/lib/drmtest.c
> @@ -123,6 +123,31 @@ static bool has_known_intel_chipset(int fd)
>  	return true;
>  }
>  
> +static char _forced_driver[16] = "";
> +
> +/**
> + * __set_forced_driver:
> + * @name: name of driver to forcibly use
> + *
> + * Set the name of a driver to use when calling #drm_open_driver with
> + * the #DRIVER_ANY flag.
> + */
> +void __set_forced_driver(const char *name)
> +{
> +	if (!name)
> +		igt_warn("No driver specified, keep default behaviour\n");
> +
> +	strncpy(_forced_driver, name, sizeof(_forced_driver) - 1);
> +}
> +
> +static const char *forced_driver(void)
> +{
> +	if (_forced_driver[0])
> +		return _forced_driver;
> +
> +	return NULL;
> +}
> +
>  #define LOCAL_I915_EXEC_VEBOX	(4 << 0)
>  /**
>   * gem_quiescent_gpu:
> @@ -212,6 +237,7 @@ static const struct module {
>  
>  static int open_device(const char *name, unsigned int chipset)
>  {
> +	const char *forced;
>  	char dev_name[16] = "";
>  	int chip = DRIVER_ANY;
>  	int fd;
> @@ -223,6 +249,12 @@ static int open_device(const char *name, unsigned int chipset)
>  	if (__get_drm_device_name(fd, dev_name, sizeof(dev_name) - 1) == -1)
>  		goto err;
>  
> +	forced = forced_driver();
> +	if (forced && chipset == DRIVER_ANY && !strcmp(forced, dev_name)) {
> +		igt_debug("Force option used: Using driver %s\n", dev_name);
> +		return fd;
> +	}
> +
>  	for (int start = 0, end = ARRAY_SIZE(modules) - 1; start < end; ){
>  		int mid = start + (end - start) / 2;
>  		int ret = strcmp(modules[mid].module, dev_name);
> diff --git a/lib/drmtest.h b/lib/drmtest.h
> index 96ee517e..8743b1bb 100644
> --- a/lib/drmtest.h
> +++ b/lib/drmtest.h
> @@ -52,6 +52,8 @@
>   */
>  #define DRIVER_ANY 	~(DRIVER_VGEM)
>  
> +void __set_forced_driver(const char *name);
> +
>  /**
>   * ARRAY_SIZE:
>   * @arr: static array
> diff --git a/lib/igt_core.c b/lib/igt_core.c
> index 64883d64..50d6008f 100644
> --- a/lib/igt_core.c
> +++ b/lib/igt_core.c
> @@ -647,6 +647,11 @@ static void common_init_env(void)
>  	igt_frame_dump_path = getenv("IGT_FRAME_DUMP_PATH");
>  
>  	stderr_needs_sentinel = getenv("IGT_SENTINEL_ON_STDERR") != NULL;
> +
> +	env = getenv("IGT_FORCE_DRIVER");
> +	if (env) {
> +		__set_forced_driver(env);
> +	}
>  }
>  
>  static int common_init(int *argc, char **argv,
> -- 
> 2.19.1
>