[igt-dev] [PATCH i-g-t v4 2/2] Add multi-device selection for IGT

Arkadiusz Hiler arkadiusz.hiler at intel.com
Wed Aug 21 07:56:47 UTC 2019


On Mon, Aug 12, 2019 at 10:47:18AM +0200, Zbigniew Kempczyński wrote:
> New IGT command line argument --device as well as IGT_DEVICE enviroment
> were added to allow selecting device using multi-device selection API.
> 
> Signed-off-by: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
> Cc: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Cc: Petri Latvala <petri.latvala at intel.com>
> ---
>  lib/drmtest.c  | 188 ++++++++++++++++++++++++++++++++++++++++++++++++-
>  lib/drmtest.h  |   9 +++
>  lib/igt_core.c |  13 ++++
>  3 files changed, 208 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/drmtest.c b/lib/drmtest.c
> index c379a7b7..c01a88a9 100644
> --- a/lib/drmtest.c
> +++ b/lib/drmtest.c
> @@ -55,6 +55,7 @@
>  #include "igt_gt.h"
>  #include "igt_kmod.h"
>  #include "igt_sysfs.h"
> +#include "igt_device_scan.h"
>  #include "version.h"
>  #include "config.h"
>  #include "intel_reg.h"
> @@ -289,25 +290,208 @@ static int __open_driver(const char *base, int offset, unsigned int chipset)
>  	return __search_and_open(base, offset, chipset);
>  }
>  
> +static int __open_driver_exact(const char *name, unsigned int chipset)
> +{
> +	static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
> +	int fd;
> +
> +	fd = open_device(name, chipset);
> +	if (fd != -1)
> +		return fd;
> +
> +	pthread_mutex_lock(&mutex);
> +	for (const struct module *m = modules; m->module; m++) {
> +		if (chipset & m->bit) {
> +			if (m->modprobe)
> +				m->modprobe(m->module);
> +			else
> +				modprobe(m->module);
> +		}
> +	}
> +	pthread_mutex_unlock(&mutex);
> +
> +	return open_device(name, chipset);
> +}
> +
> +/*
> + * For compatibility mode when multiple --device argument were passed
> + * this function tries to be smart enough to handle tests which opens
> + * more than single device. It iterates over filter list and
> + * compares requested chipset to card chipset (or any).

How do you imagine the new API working with multi-device tests that open
more than one node?

Currently some of our tests are depending on haxes to excercise that.
Let's take kms_prime:

static void run_test_crc(int export_chipset, int import_chipset)
{

	int exporter_fd = drm_open_driver(export_chipset);
	int importer_fd = drm_open_driver_master(import_chipset);
	/* ... */
}

igt_subtest("basic-crc")
		run_test_crc(DRIVER_VGEM, DRIVER_ANY);

This works only because:

/*
 * 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.
 */
#define DRIVER_ANY 	~(DRIVER_VGEM)


So I am expecting similar tests in the future that are touching real
devices. With the current device handling this would not work as
specifying double DRIVER_ANY would result in the same device being
opened twice.

I was initially thinking about something like:

int drm_open_other_device(int chipset, int other_than_fd);

int exporter_fd = drm_open_driver(DRIVER_ANY);
int importer_fd = drm_open_other_device(DRIVER_ANY, exporter_fd);


Now, with the new API I would like to be able to:
1. open two different devices, even without using the filters at all
2. select which device is exporter and importer via --device filters

I see that we have drm_open_card_with_nth_filter, but this requires a
filter, so using it in the tests would require --device, so point 1 is
not addressed.

Do you have any thoughts on that?

To be clear - I am not requesting anything to be implemented here. It's
better to leave that to people actually interested in similar tests. I
just want to make sure the current implementation is flexible enough to
accomodate for that and it won't result in a complete re-write of the
device selection logic :-)

> + * Returns:
> + * True if card according to filters added and chipset was found,
> + * false othwerwise.
> + */
> +static bool __find_card_with_chipset(int chipset, struct igt_device_card *card)
> +{
> +	int i, n = igt_device_filter_count();
> +	const char *filter;
> +	bool match;
> +
> +	for (i = 0; i < n; i++) {
> +		filter = igt_device_filter_get(i);
> +		match = igt_device_card_match(filter, card);
> +		if (match && (card->chipset == chipset ||
> +			      card->chipset == DRIVER_ANY)) {
> +			return true;
> +		}
> +	}
> +
> +	return false;
> +}
> +
>  /**
>   * __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
> + * Function opens device in the following order:
> + * 1. when --device arguments are present device scanning will be executed,
> + * then filter argument is used to find matching one.
> + * 2. compatibility mode - 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)
>  {
> +	int n = igt_device_filter_count();
> +
> +	if (n) {

if (igt_device_filter_count() > 0)
should be nicer to read, there are few more instances

> +		bool found;
> +		struct igt_device_card card;
> +
> +		found = __find_card_with_chipset(chipset, &card);
> +		if (!found || !strlen(card.card))

It would be nice to log (I suggest WARN level) that we do have filters
but failed to match any to provided 'int chipset'.

> +			return -1;
> +

Here we can mention that we succeded (INFO) + some context (which
filter, device, etc).

I think we should be as explicit on which node/card was used when
possible. Less surprises and debugging for users who don't know why
something skips or which device was opened exactely.

> +		return __open_driver_exact(card.card, chipset);
> +	}
> +
>  	return __open_driver("/dev/dri/card", 0, chipset);
>  }
>  
> -static int __drm_open_driver_render(int chipset)
> +int __drm_open_driver_render(int chipset)
>  {
> +	int n = igt_device_filter_count();
> +
> +	if (n) {
> +		bool found;
> +		struct igt_device_card card;
> +
> +		found = __find_card_with_chipset(chipset, &card);
> +		if (!found || !strlen(card.render))
> +			return -1;
> +
> +		return __open_driver_exact(card.render, chipset);
> +	}
> +
>  	return __open_driver("/dev/dri/renderD", 128, chipset);
>  }
>  
> +static int __drm_open_with_nth_filter(int num, int chipset, bool open_render)
> +{
> +	struct igt_device_card card;
> +	const char *filter, *devname;
> +	bool match;
> +	int n = igt_device_filter_count();
> +
> +	if (!n || num < 0 || num >= n) {
> +		igt_warn("No device filter num == %d passed\n", num);
> +		return -1;
> +	}
> +
> +	filter = igt_device_filter_get(num);
> +	match = igt_device_card_match(filter, &card);
> +	if (!match) {
> +		igt_warn("No device match filter: %s\n", filter);
> +		return -1;
> +	}
> +
> +	if (!strlen(card.card) && !strlen(card.render))
> +		return -1;
> +
> +	devname = open_render ? card.render : card.card;
> +	if (!strlen(devname)) {
> +		igt_warn("No %s node matching filter: %s\n",
> +			 open_render ? "render" : "card", filter);
> +		return -1;
> +	}
> +	return __open_driver_exact(devname, chipset);
> +}
> +
> +/**
> + * drm_open_card_with_nth_filter:
> + * @num: number of --device argument
> + * @chipset: OR'd flags for each chipset to search, eg. #DRIVER_INTEL
> + *
> + * Open /dev/dri/cardX device using multi-device selection API.
> + * When test require to open more than one device selection uses filter
> + * passed as --device argument. Arguments @num indicate filter number
> + * and @chipset expected device card chipset.
> + *
> + * An open DRM fd or -1 on error
> + */
> +int drm_open_card_with_nth_filter(int num, int chipset)
> +{
> +	return __drm_open_with_nth_filter(num, chipset, false);
> +}

Related to the comments above - I would be surprised if any of the test
would be using that directly, as it forces using filters.

> +
> +/**
> + * drm_open_render_with_nth_filter:
> + * @num: number of --device argument
> + * @chipset: OR'd flags for each chipset to search, eg. #DRIVER_INTEL
> + *
> + * Open /dev/dri/renderDX device using multi-device selection API.
> + *
> + * When test require to open more than one device selection uses filter
> + * passed as --device argument. Arguments @num indicate filter number
> + * and @chipset expected device card chipset.
> + *
> + * An open DRM fd or -1 on error
> + */
> +int drm_open_render_with_nth_filter(int num, int chipset)
> +{
> +	return __drm_open_with_nth_filter(num, chipset, true);
> +}
> +
> +/**
> + * drm_open_card:
> + * @card: pointer to igt_device_card structure
> + *
> + * Open /dev/dri/cardX device using multi-device selection API.
> + *
> + * Require filled @card argument (see igt_device_card_match() function).
> + *
> + * An open DRM fd or -1 on error
> + */
> +int drm_open_card(struct igt_device_card *card)
> +{
> +	if (!card || !strlen(card->card))
> +		return -1;
> +
> +	return __open_driver_exact(card->card, card->chipset);
> +}
> +
> +/**
> + * drm_open_render:
> + * @card: pointer to igt_device_card structure
> + *
> + * Open /dev/dri/renderDX device using multi-device selection API.
> + * Require filled @card argument (see igt_device_card_match() function).
> + *
> + * An open DRM fd or -1 on error
> + */
> +int drm_open_render(struct igt_device_card *card)
> +{
> +	if (!card || !strlen(card->render))
> +		return -1;
> +
> +	return __open_driver_exact(card->render, card->chipset);
> +}
> +
> +
>  static int at_exit_drm_fd = -1;
>  static int at_exit_drm_render_fd = -1;
>  
> diff --git a/lib/drmtest.h b/lib/drmtest.h
> index 614f57e6..fc2a0b57 100644
> --- a/lib/drmtest.h
> +++ b/lib/drmtest.h
> @@ -50,6 +50,7 @@
>  #define DRIVER_AMDGPU	(1 << 3)
>  #define DRIVER_V3D	(1 << 4)
>  #define DRIVER_PANFROST	(1 << 5)
> +
>  /*
>   * 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
> @@ -81,6 +82,14 @@ int drm_open_driver(int chipset);
>  int drm_open_driver_master(int chipset);
>  int drm_open_driver_render(int chipset);
>  int __drm_open_driver(int chipset);
> +int __drm_open_driver_render(int chipset);
> +
> +/* Multi device API */
> +int drm_open_card_with_nth_filter(int num, int chipset);
> +int drm_open_render_with_nth_filter(int num, int chipset);
> +struct igt_device_card;
> +int drm_open_card(struct igt_device_card *card);
> +int drm_open_render(struct igt_device_card *card);
>  
>  void gem_quiescent_gpu(int fd);
>  
> diff --git a/lib/igt_core.c b/lib/igt_core.c
> index 1cbb09f9..9b851175 100644
> --- a/lib/igt_core.c
> +++ b/lib/igt_core.c
> @@ -71,6 +71,7 @@
>  #include "igt_sysrq.h"
>  #include "igt_rc.h"
>  #include "igt_list.h"
> +#include "igt_device_scan.h"
>  
>  #define UNW_LOCAL_ONLY
>  #include <libunwind.h>
> @@ -304,6 +305,7 @@ enum {
>  	OPT_DEBUG,
>  	OPT_INTERACTIVE_DEBUG,
>  	OPT_SKIP_CRC,
> +	OPT_DEVICE,
>  	OPT_HELP = 'h'
>  };
>  
> @@ -624,6 +626,7 @@ static void print_usage(const char *help_str, bool output_on_stderr)
>  		   "  --skip-crc-compare\n"
>  		   "  --help-description\n"
>  		   "  --describe\n"
> +		   "  --device filter\n"
>  		   "  --help|-h\n");
>  	if (help_str)
>  		fprintf(f, "%s\n", help_str);
> @@ -725,6 +728,11 @@ static void common_init_env(void)
>  	if (env) {
>  		__set_forced_driver(env);
>  	}
> +
> +	env = getenv("IGT_DEVICE");
> +	if (env) {
> +		igt_device_filter_add(env);
> +	}
>  }
>  
>  static int common_init(int *argc, char **argv,
> @@ -743,6 +751,7 @@ static int common_init(int *argc, char **argv,
>  		{"debug",             optional_argument, NULL, OPT_DEBUG},
>  		{"interactive-debug", optional_argument, NULL, OPT_INTERACTIVE_DEBUG},
>  		{"skip-crc-compare",  no_argument,       NULL, OPT_SKIP_CRC},
> +		{"device",            required_argument, NULL, OPT_DEVICE},
>  		{"help",              no_argument,       NULL, OPT_HELP},
>  		{0, 0, 0, 0}
>  	};
> @@ -865,6 +874,10 @@ static int common_init(int *argc, char **argv,
>  		case OPT_SKIP_CRC:
>  			igt_skip_crc_compare = true;
>  			goto out;
> +		case OPT_DEVICE:
> +			assert(optarg);
> +			igt_device_filter_add(optarg);
> +			break;
>  		case OPT_HELP:
>  			print_usage(help_str, false);
>  			ret = -1;

So first we add filters via IGT_DEVICE and then we *append* filters
passed via --device.

So `export IGT_DEVICE=yyy; ./test --device zzz` is equivalent to '--device yyy;zzz'.

This is surprising to me - I would expect only 'zzz' to take effect.

There were some other people asking how options, which you can configure
in a multiple ways, should be handled. I think that the consensus was
that you overwrite them completely in the following order.
 * .igtrc has the lowest importance
 * ENV variable overwrites whatever is specified in .igtrc
 * --switch on a test overwrites everything else

I guess we should put that in the docs.

-- 
Cheers,
Arek


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