EXT: [PATCH weston v10 1/1] weston: support clone mode on DRM-frontend

Ray, Ian (GE Healthcare) ian.ray at ge.com
Fri Jun 29 10:08:17 UTC 2018



> On 6 Jun 2018, at 14.30, Pekka Paalanen <ppaalanen at gmail.com> wrote:
> 
> From: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> 
> Add a new output section key "same-as" for configuring clone mode. An
> output marked "same-as" another output will be configured identically to
> the other output.
> 
> The current implementation supports only CRTC sharing for clone mode.
> Independent CRTC clone mode cannot be supported until output layout
> logic is moved from libweston into the frontend and libweston's damage
> tracking issues stemming from overlapping outputs are solved.
> 
> Quite a lot of infrastructure is needed to properly configure clone
> mode. The implemented logic allows easy addition of independent CRTC
> clone mode once libweston supports it. The idea is that wet_layoutput is
> the item to be laid out and all weston_outputs a wet_layoutput
> contains show exactly the same area of the desktop.
> 
> The configuration logic attempts to automatically fall back to creating
> more weston_outputs when all heads do not work under the same
> weston_output. For now, the fallback path ends with an error message.
> 
> Enabling a weston_output is bit complicated, because one needs to first
> collect all relevant heads, try to attach them all to the weston_output,
> and then back up head by head until enabling the weston_output succeeds.
> A new weston_output is created for the left-over heads and the process
> is repeated.
> 
> CRTC-sharing clone mode is the most efficient clone mode, offering
> synchronized scanout timings, but it is not always supported by
> hardware.
> 

Reviewed-by: Ian Ray <ian.ray at ge.com>


> v10:
> - rebased trivial conflicts in man page
> - switch to gitlab issue URL
> 
> v9:
> - replace weston_compositor_set_heads_changed_cb() with
>  weston_compositor_add_heads_changed_listener()
> - remove workaround in simple_head_enable()
> 
> v6:
> - Add man-page note about cms-colord.
> - Don't create an output just to turn it off.
> 
> Fixes: https://gitlab.freedesktop.org/wayland/weston/issues/22
> 
> Signed-off-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> Acked-by: Derek Foreman <derekf at osg.samsung.com>
> Acked-by: Daniel Stone <daniels at collabora.com>
> ---
> compositor/main.c  | 492 ++++++++++++++++++++++++++++++++++++++++++++++++++---
> man/weston-drm.man |  12 ++
> 2 files changed, 484 insertions(+), 20 deletions(-)
> 
> diff --git a/compositor/main.c b/compositor/main.c
> index e84857f7..920d14d7 100644
> --- a/compositor/main.c
> +++ b/compositor/main.c
> @@ -71,11 +71,41 @@ struct wet_output_config {
> };
> 
> struct wet_compositor;
> +struct wet_layoutput;
> 
> struct wet_head_tracker {
> 	struct wl_listener head_destroy_listener;
> };
> 
> +/** User data for each weston_output */
> +struct wet_output {
> +	struct weston_output *output;
> +	struct wl_listener output_destroy_listener;
> +	struct wet_layoutput *layoutput;
> +	struct wl_list link;	/**< in wet_layoutput::output_list */
> +};
> +
> +#define MAX_CLONE_HEADS 16
> +
> +struct wet_head_array {
> +	struct weston_head *heads[MAX_CLONE_HEADS];	/**< heads to add */
> +	unsigned n;				/**< the number of heads */
> +};
> +
> +/** A layout output
> + *
> + * Contains wet_outputs that are all clones (independent CRTCs).
> + * Stores output layout information in the future.
> + */
> +struct wet_layoutput {
> +	struct wet_compositor *compositor;
> +	struct wl_list compositor_link;	/**< in wet_compositor::layoutput_list */
> +	struct wl_list output_list;	/**< wet_output::link */
> +	char *name;
> +	struct weston_config_section *section;
> +	struct wet_head_array add;	/**< tmp: heads to add as clones */
> +};
> +
> struct wet_compositor {
> 	struct weston_compositor *compositor;
> 	struct weston_config *config;
> @@ -84,6 +114,7 @@ struct wet_compositor {
> 	struct wl_listener heads_changed_listener;
> 	int (*simple_output_configure)(struct weston_output *output);
> 	bool init_failed;
> +	struct wl_list layoutput_list;	/**< wet_layoutput::compositor_link */
> };
> 
> static FILE *weston_logfile = NULL;
> @@ -1163,12 +1194,6 @@ simple_head_enable(struct wet_compositor *wet, struct weston_head *head)
> 	struct weston_output *output;
> 	int ret = 0;
> 
> -	/* Workaround for repeated DRM backend "off" setting.
> -	 * For any other case, we should not have an attached head that is not
> -	 * enabled. */
> -	if (weston_head_get_output(head))
> -		return;
> -
> 	output = weston_compositor_create_output_with_head(wet->compositor,
> 							   head);
> 	if (!output) {
> @@ -1190,10 +1215,6 @@ simple_head_enable(struct wet_compositor *wet, struct weston_head *head)
> 		return;
> 	}
> 
> -	/* Escape hatch for DRM backend "off" setting. */
> -	if (ret > 0)
> -		return;
> -
> 	if (weston_output_enable(output) < 0) {
> 		weston_log("Enabling output \"%s\" failed.\n",
> 			   weston_head_get_name(head));
> @@ -1289,32 +1310,29 @@ configure_input_device(struct weston_compositor *compositor,
> }
> 
> static int
> -drm_backend_output_configure(struct weston_output *output)
> +drm_backend_output_configure(struct weston_output *output,
> +			     struct weston_config_section *section)
> {
> -	struct weston_config *wc = wet_get_config(output->compositor);
> 	struct wet_compositor *wet = to_wet_compositor(output->compositor);
> -	struct weston_config_section *section;
> -	const struct weston_drm_output_api *api = weston_drm_output_get_api(output->compositor);
> +	const struct weston_drm_output_api *api;
> 	enum weston_drm_backend_output_mode mode =
> 		WESTON_DRM_BACKEND_OUTPUT_PREFERRED;
> -
> 	char *s;
> 	char *modeline = NULL;
> 	char *gbm_format = NULL;
> 	char *seat = NULL;
> 
> +	api = weston_drm_output_get_api(output->compositor);
> 	if (!api) {
> 		weston_log("Cannot use weston_drm_output_api.\n");
> 		return -1;
> 	}
> 
> -	section = weston_config_get_section(wc, "output", "name", output->name);
> 	weston_config_section_get_string(section, "mode", &s, "preferred");
> 
> 	if (strcmp(s, "off") == 0) {
> -		weston_output_disable(output);
> -		free(s);
> -		return 1;
> +		assert(0 && "off was supposed to be pruned");
> +		return -1;
> 	} else if (wet->drm_use_current_mode || strcmp(s, "current") == 0) {
> 		mode = WESTON_DRM_BACKEND_OUTPUT_CURRENT;
> 	} else if (strcmp(s, "preferred") != 0) {
> @@ -1347,6 +1365,434 @@ drm_backend_output_configure(struct weston_output *output)
> 	return 0;
> }
> 
> +/* Find the output section to use for configuring the output with the
> + * named head. If an output section with the given name contains
> + * a "same-as" key, ignore all other settings in the output section and
> + * instead find an output section named by the "same-as". Do this
> + * recursively.
> + */
> +static struct weston_config_section *
> +drm_config_find_controlling_output_section(struct weston_config *config,
> +					   const char *head_name)
> +{
> +	struct weston_config_section *section;
> +	char *same_as;
> +	int depth = 0;
> +
> +	same_as = strdup(head_name);
> +	do {
> +		section = weston_config_get_section(config, "output",
> +						    "name", same_as);
> +		if (!section && depth > 0)
> +			weston_log("Configuration error: "
> +				   "output section referred to with "
> +				   "'same-as=%s' not found.\n", same_as);
> +
> +		free(same_as);
> +
> +		if (!section)
> +			return NULL;
> +
> +		if (++depth > 10) {
> +			weston_log("Configuration error: "
> +				   "'same-as' nested too deep for output '%s'.\n",
> +				   head_name);
> +			return NULL;
> +		}
> +
> +		weston_config_section_get_string(section, "same-as",
> +						 &same_as, NULL);
> +	} while (same_as);
> +
> +	return section;
> +}
> +
> +static struct wet_layoutput *
> +wet_compositor_create_layoutput(struct wet_compositor *compositor,
> +				const char *name,
> +				struct weston_config_section *section)
> +{
> +	struct wet_layoutput *lo;
> +
> +	lo = zalloc(sizeof *lo);
> +	if (!lo)
> +		return NULL;
> +
> +	lo->compositor = compositor;
> +	wl_list_insert(compositor->layoutput_list.prev, &lo->compositor_link);
> +	wl_list_init(&lo->output_list);
> +	lo->name = strdup(name);
> +	lo->section = section;
> +
> +	return lo;
> +}
> +
> +static void
> +wet_layoutput_destroy(struct wet_layoutput *lo)
> +{
> +	wl_list_remove(&lo->compositor_link);
> +	assert(wl_list_empty(&lo->output_list));
> +	free(lo->name);
> +	free(lo);
> +}
> +
> +static void
> +wet_output_handle_destroy(struct wl_listener *listener, void *data)
> +{
> +	struct wet_output *output;
> +
> +	output = wl_container_of(listener, output, output_destroy_listener);
> +	assert(output->output == data);
> +
> +	output->output = NULL;
> +	wl_list_remove(&output->output_destroy_listener.link);
> +}
> +
> +static struct wet_output *
> +wet_layoutput_create_output(struct wet_layoutput *lo, const char *name)
> +{
> +	struct wet_output *output;
> +
> +	output = zalloc(sizeof *output);
> +	if (!output)
> +		return NULL;
> +
> +	output->output =
> +		weston_compositor_create_output(lo->compositor->compositor,
> +						name);
> +	if (!output) {
> +		free(output);
> +		return NULL;
> +	}
> +
> +	output->layoutput = lo;
> +	wl_list_insert(lo->output_list.prev, &output->link);
> +	output->output_destroy_listener.notify = wet_output_handle_destroy;
> +	weston_output_add_destroy_listener(output->output,
> +					   &output->output_destroy_listener);
> +
> +	return output;
> +}
> +
> +static struct wet_output *
> +wet_output_from_weston_output(struct weston_output *base)
> +{
> +	struct wl_listener *lis;
> +
> +	lis = weston_output_get_destroy_listener(base,
> +						 wet_output_handle_destroy);
> +	if (!lis)
> +		return NULL;
> +
> +	return container_of(lis, struct wet_output, output_destroy_listener);
> +}
> +
> +static void
> +wet_output_destroy(struct wet_output *output)
> +{
> +	if (output->output)
> +		weston_output_destroy(output->output);
> +
> +	wl_list_remove(&output->link);
> +	free(output);
> +}
> +
> +static struct wet_layoutput *
> +wet_compositor_find_layoutput(struct wet_compositor *wet, const char *name)
> +{
> +	struct wet_layoutput *lo;
> +
> +	wl_list_for_each(lo, &wet->layoutput_list, compositor_link)
> +		if (strcmp(lo->name, name) == 0)
> +			return lo;
> +
> +	return NULL;
> +}
> +
> +static void
> +wet_compositor_layoutput_add_head(struct wet_compositor *wet,
> +				  const char *output_name,
> +				  struct weston_config_section *section,
> +				  struct weston_head *head)
> +{
> +	struct wet_layoutput *lo;
> +
> +	lo = wet_compositor_find_layoutput(wet, output_name);
> +	if (!lo) {
> +		lo = wet_compositor_create_layoutput(wet, output_name, section);
> +		if (!lo)
> +			return;
> +	}
> +
> +	if (lo->add.n + 1 >= ARRAY_LENGTH(lo->add.heads))
> +		return;
> +
> +	lo->add.heads[lo->add.n++] = head;
> +}
> +
> +static void
> +wet_compositor_destroy_layout(struct wet_compositor *wet)
> +{
> +	struct wet_layoutput *lo, *lo_tmp;
> +	struct wet_output *output, *output_tmp;
> +
> +	wl_list_for_each_safe(lo, lo_tmp,
> +			      &wet->layoutput_list, compositor_link) {
> +		wl_list_for_each_safe(output, output_tmp,
> +				      &lo->output_list, link) {
> +			wet_output_destroy(output);
> +		}
> +		wet_layoutput_destroy(lo);
> +	}
> +}
> +
> +static void
> +drm_head_prepare_enable(struct wet_compositor *wet,
> +			struct weston_head *head)
> +{
> +	const char *name = weston_head_get_name(head);
> +	struct weston_config_section *section;
> +	char *output_name = NULL;
> +	char *mode = NULL;
> +
> +	section = drm_config_find_controlling_output_section(wet->config, name);
> +	if (section) {
> +		/* skip outputs that are explicitly off, the backend turns
> +		 * them off automatically.
> +		 */
> +		weston_config_section_get_string(section, "mode", &mode, NULL);
> +		if (mode && strcmp(mode, "off") == 0) {
> +			free(mode);
> +			return;
> +		}
> +		free(mode);
> +
> +		weston_config_section_get_string(section, "name",
> +						 &output_name, NULL);
> +		assert(output_name);
> +
> +		wet_compositor_layoutput_add_head(wet, output_name,
> +						  section, head);
> +		free(output_name);
> +	} else {
> +		wet_compositor_layoutput_add_head(wet, name, NULL, head);
> +	}
> +}
> +
> +static void
> +drm_try_attach(struct weston_output *output,
> +	       struct wet_head_array *add,
> +	       struct wet_head_array *failed)
> +{
> +	unsigned i;
> +
> +	/* try to attach all heads, this probably succeeds */
> +	for (i = 0; i < add->n; i++) {
> +		if (!add->heads[i])
> +			continue;
> +
> +		if (weston_output_attach_head(output, add->heads[i]) < 0) {
> +			assert(failed->n < ARRAY_LENGTH(failed->heads));
> +
> +			failed->heads[failed->n++] = add->heads[i];
> +			add->heads[i] = NULL;
> +		}
> +	}
> +}
> +
> +static int
> +drm_try_enable(struct weston_output *output,
> +	       struct wet_head_array *undo,
> +	       struct wet_head_array *failed)
> +{
> +	/* Try to enable, and detach heads one by one until it succeeds. */
> +	while (!output->enabled) {
> +		if (weston_output_enable(output) == 0)
> +			return 0;
> +
> +		/* the next head to drop */
> +		while (undo->n > 0 && undo->heads[--undo->n] == NULL)
> +			;
> +
> +		/* No heads left to undo and failed to enable. */
> +		if (undo->heads[undo->n] == NULL)
> +			return -1;
> +
> +		assert(failed->n < ARRAY_LENGTH(failed->heads));
> +
> +		/* undo one head */
> +		weston_head_detach(undo->heads[undo->n]);
> +		failed->heads[failed->n++] = undo->heads[undo->n];
> +		undo->heads[undo->n] = NULL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int
> +drm_try_attach_enable(struct weston_output *output, struct wet_layoutput *lo)
> +{
> +	struct wet_head_array failed = {};
> +	unsigned i;
> +
> +	assert(!output->enabled);
> +
> +	drm_try_attach(output, &lo->add, &failed);
> +	if (drm_backend_output_configure(output, lo->section) < 0)
> +		return -1;
> +
> +	if (drm_try_enable(output, &lo->add, &failed) < 0)
> +		return -1;
> +
> +	/* For all successfully attached/enabled heads */
> +	for (i = 0; i < lo->add.n; i++)
> +		if (lo->add.heads[i])
> +			wet_head_tracker_create(lo->compositor,
> +						lo->add.heads[i]);
> +
> +	/* Push failed heads to the next round. */
> +	lo->add = failed;
> +
> +	return 0;
> +}
> +
> +static int
> +drm_process_layoutput(struct wet_compositor *wet, struct wet_layoutput *lo)
> +{
> +	struct wet_output *output, *tmp;
> +	char *name = NULL;
> +	int ret;
> +
> +	/*
> +	 *   For each existing wet_output:
> +	 *     try attach
> +	 *   While heads left to enable:
> +	 *     Create output
> +	 *     try attach, try enable
> +	 */
> +
> +	wl_list_for_each_safe(output, tmp, &lo->output_list, link) {
> +		struct wet_head_array failed = {};
> +
> +		if (!output->output) {
> +			/* Clean up left-overs from destroyed heads. */
> +			wet_output_destroy(output);
> +			continue;
> +		}
> +
> +		assert(output->output->enabled);
> +
> +		drm_try_attach(output->output, &lo->add, &failed);
> +		lo->add = failed;
> +		if (lo->add.n == 0)
> +			return 0;
> +	}
> +
> +	if (!weston_compositor_find_output_by_name(wet->compositor, lo->name))
> +		name = strdup(lo->name);
> +
> +	while (lo->add.n > 0) {
> +		if (!wl_list_empty(&lo->output_list)) {
> +			weston_log("Error: independent-CRTC clone mode is not implemented.\n");
> +			return -1;
> +		}
> +
> +		if (!name) {
> +			ret = asprintf(&name, "%s:%s", lo->name,
> +				       weston_head_get_name(lo->add.heads[0]));
> +			if (ret < 0)
> +				return -1;
> +		}
> +		output = wet_layoutput_create_output(lo, name);
> +		free(name);
> +		name = NULL;
> +
> +		if (!output)
> +			return -1;
> +
> +		if (drm_try_attach_enable(output->output, lo) < 0) {
> +			wet_output_destroy(output);
> +			return -1;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int
> +drm_process_layoutputs(struct wet_compositor *wet)
> +{
> +	struct wet_layoutput *lo;
> +	int ret = 0;
> +
> +	wl_list_for_each(lo, &wet->layoutput_list, compositor_link) {
> +		if (lo->add.n == 0)
> +			continue;
> +
> +		if (drm_process_layoutput(wet, lo) < 0) {
> +			lo->add = (struct wet_head_array){};
> +			ret = -1;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static void
> +drm_head_disable(struct weston_head *head)
> +{
> +	struct weston_output *output_base;
> +	struct wet_output *output;
> +	struct wet_head_tracker *track;
> +
> +	track = wet_head_tracker_from_head(head);
> +	if (track)
> +		wet_head_tracker_destroy(track);
> +
> +	output_base = weston_head_get_output(head);
> +	assert(output_base);
> +	output = wet_output_from_weston_output(output_base);
> +	assert(output && output->output == output_base);
> +
> +	weston_head_detach(head);
> +	if (count_remaining_heads(output->output, NULL) == 0)
> +		wet_output_destroy(output);
> +}
> +
> +static void
> +drm_heads_changed(struct wl_listener *listener, void *arg)
> +{
> +	struct weston_compositor *compositor = arg;
> +	struct wet_compositor *wet = to_wet_compositor(compositor);
> +	struct weston_head *head = NULL;
> +	bool connected;
> +	bool enabled;
> +	bool changed;
> +
> +	/* We need to collect all cloned heads into outputs before enabling the
> +	 * output.
> +	 */
> +	while ((head = weston_compositor_iterate_heads(compositor, head))) {
> +		connected = weston_head_is_connected(head);
> +		enabled = weston_head_is_enabled(head);
> +		changed = weston_head_is_device_changed(head);
> +
> +		if (connected && !enabled) {
> +			drm_head_prepare_enable(wet, head);
> +		} else if (!connected && enabled) {
> +			drm_head_disable(head);
> +		} else if (enabled && changed) {
> +			weston_log("Detected a monitor change on head '%s', "
> +				   "not bothering to do anything about it.\n",
> +				   weston_head_get_name(head));
> +		}
> +		weston_head_reset_device_changed(head);
> +	}
> +
> +	if (drm_process_layoutputs(wet) < 0)
> +		wet->init_failed = true;
> +}
> +
> static int
> load_drm_backend(struct weston_compositor *c,
> 		 int *argc, char **argv, struct weston_config *wc)
> @@ -1382,7 +1828,9 @@ load_drm_backend(struct weston_compositor *c,
> 	config.base.struct_size = sizeof(struct weston_drm_backend_config);
> 	config.configure_device = configure_input_device;
> 
> -	wet_set_simple_head_configurator(c, drm_backend_output_configure);
> +	wet->heads_changed_listener.notify = drm_heads_changed;
> +	weston_compositor_add_heads_changed_listener(c,
> +						&wet->heads_changed_listener);
> 
> 	ret = weston_compositor_load_backend(c, WESTON_BACKEND_DRM,
> 					     &config.base);
> @@ -1921,6 +2369,8 @@ int main(int argc, char *argv[])
> 		{ WESTON_OPTION_BOOLEAN, "wait-for-debugger", 0, &wait_for_debugger },
> 	};
> 
> +	wl_list_init(&wet.layoutput_list);
> +
> 	if (os_fd_set_cloexec(fileno(stdin))) {
> 		printf("Unable to set stdin as close on exec().\n");
> 		return EXIT_FAILURE;
> @@ -2108,6 +2558,8 @@ int main(int argc, char *argv[])
> 	ret = wet.compositor->exit_code;
> 
> out:
> +	wet_compositor_destroy_layout(&wet);
> +
> 	/* free(NULL) is valid, and it won't be NULL if it's used */
> 	free(wet.parsed_options);
> 
> diff --git a/man/weston-drm.man b/man/weston-drm.man
> index d4cb75a7..c9e69151 100644
> --- a/man/weston-drm.man
> +++ b/man/weston-drm.man
> @@ -83,6 +83,18 @@ and possibly flipped. Possible values are
> \fBpixman-shadow\fR=\fIboolean\fR
> If using the Pixman-renderer, use shadow framebuffers. Defaults to
> .BR true .
> +.TP
> +\fBsame-as\fR=\fIname\fR
> +Make this output (connector) a clone of another. The argument
> +.IR name " is the "
> +.BR name " value of another output section. The
> +referred to output section must exist. When this key is present in an
> +output section, all other keys have no effect on the configuration.
> +
> +NOTE: cms-colord plugin does not work correctly with this option. The plugin
> +chooses an arbitrary monitor to load the color profile for, but the
> +profile is applied equally to all cloned monitors regardless of their
> +properties.
> .
> .\" ***************************************************************
> .SH OPTIONS
> -- 
> 2.16.4
> 
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