45  * DRM device drivers can provide to userspace CRC information of each frame as
49  * file dri/0/crtc-N/crc/control in debugfs, with N being the :ref:`index of
51  * driver-specific) and the "auto" keyword, which will let the driver select a
52  * default source of frame CRCs for this CRTC.
54  * Once frame CRC generation is enabled, userspace can capture them by reading
55  * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame
58  * of CRC fields is source-specific.
61  * the frame contents as supplied by userspace (eDP 1.3), in general the CRC
62  * computation is performed in an unspecified way and on frame contents that have
64  * rely on being able to generate matching CRC values for the frame contents that
73  * may result in a commit (even a full modeset).
75  * CRC results must be reliable across non-full-modeset atomic commits, so if a
77  * CRC generation, then the driver must mark that commit as a full modeset
79  * consistent results, generic userspace must re-setup CRC generation after a
85 	struct drm_crtc *crtc = m->private;  in crc_control_show()
87 	if (crtc->funcs->get_crc_sources) {  in crc_control_show()
89 		const char *const *sources = crtc->funcs->get_crc_sources(crtc,  in crc_control_show()
98 			if (!crtc->funcs->verify_crc_source(crtc, sources[i],  in crc_control_show()
100 				if (strcmp(sources[i], crtc->crc.source))  in crc_control_show()
109 	seq_printf(m, "%s*\n", crtc->crc.source);  in crc_control_show()
115 	struct drm_crtc *crtc = inode->i_private;  in crc_control_open()
123 	struct seq_file *m = file->private_data;  in crc_control_write()
124 	struct drm_crtc *crtc = m->private;  in crc_control_write()
125 	struct drm_crtc_crc *crc = &crtc->crc;  in crc_control_write()
133 	if (len > PAGE_SIZE - 1) {  in crc_control_write()
136 		return -E2BIG;  in crc_control_write()
143 	if (source[len - 1] == '\n')  in crc_control_write()
144 		source[len - 1] = '\0';  in crc_control_write()
146 	ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt);  in crc_control_write()
152 	spin_lock_irq(&crc->lock);  in crc_control_write()
154 	if (crc->opened) {  in crc_control_write()
155 		spin_unlock_irq(&crc->lock);  in crc_control_write()
157 		return -EBUSY;  in crc_control_write()
160 	kfree(crc->source);  in crc_control_write()
161 	crc->source = source;  in crc_control_write()
163 	spin_unlock_irq(&crc->lock);  in crc_control_write()
180 	assert_spin_locked(&crc->lock);  in crtc_crc_data_count()
181 	return CIRC_CNT(crc->head, crc->tail, DRM_CRC_ENTRIES_NR);  in crtc_crc_data_count()
186 	kfree(crc->entries);  in crtc_crc_cleanup()
187 	crc->overflow = false;  in crtc_crc_cleanup()
188 	crc->entries = NULL;  in crtc_crc_cleanup()
189 	crc->head = 0;  in crtc_crc_cleanup()
190 	crc->tail = 0;  in crtc_crc_cleanup()
191 	crc->values_cnt = 0;  in crtc_crc_cleanup()
192 	crc->opened = false;  in crtc_crc_cleanup()
197 	struct drm_crtc *crtc = inode->i_private;  in crtc_crc_open()
198 	struct drm_crtc_crc *crc = &crtc->crc;  in crtc_crc_open()
203 	if (drm_drv_uses_atomic_modeset(crtc->dev)) {  in crtc_crc_open()
204 		ret = drm_modeset_lock_single_interruptible(&crtc->mutex);  in crtc_crc_open()
208 		if (!crtc->state->active)  in crtc_crc_open()
209 			ret = -EIO;  in crtc_crc_open()
210 		drm_modeset_unlock(&crtc->mutex);  in crtc_crc_open()
216 	ret = crtc->funcs->verify_crc_source(crtc, crc->source, &values_cnt);  in crtc_crc_open()
221 		return -EINVAL;  in crtc_crc_open()
224 		return -EINVAL;  in crtc_crc_open()
228 		return -ENOMEM;  in crtc_crc_open()
230 	spin_lock_irq(&crc->lock);  in crtc_crc_open()
231 	if (!crc->opened) {  in crtc_crc_open()
232 		crc->opened = true;  in crtc_crc_open()
233 		crc->entries = entries;  in crtc_crc_open()
234 		crc->values_cnt = values_cnt;  in crtc_crc_open()
236 		ret = -EBUSY;  in crtc_crc_open()
238 	spin_unlock_irq(&crc->lock);  in crtc_crc_open()
245 	ret = crtc->funcs->set_crc_source(crtc, crc->source);  in crtc_crc_open()
252 	spin_lock_irq(&crc->lock);  in crtc_crc_open()
254 	spin_unlock_irq(&crc->lock);  in crtc_crc_open()
260 	struct drm_crtc *crtc = filep->f_inode->i_private;  in crtc_crc_release()
261 	struct drm_crtc_crc *crc = &crtc->crc;  in crtc_crc_release()
264 	spin_lock_irq(&crc->lock);  in crtc_crc_release()
265 	crc->opened = false;  in crtc_crc_release()
266 	spin_unlock_irq(&crc->lock);  in crtc_crc_release()
268 	crtc->funcs->set_crc_source(crtc, NULL);  in crtc_crc_release()
270 	spin_lock_irq(&crc->lock);  in crtc_crc_release()
272 	spin_unlock_irq(&crc->lock);  in crtc_crc_release()
278  * 1 frame field of 10 chars plus a number of CRC fields of 10 chars each, space
279  * separated, with a newline at the end and null-terminated.
287 	struct drm_crtc *crtc = filep->f_inode->i_private;  in crtc_crc_read()
288 	struct drm_crtc_crc *crc = &crtc->crc;  in crtc_crc_read()
293 	spin_lock_irq(&crc->lock);  in crtc_crc_read()
295 	if (!crc->source) {  in crtc_crc_read()
296 		spin_unlock_irq(&crc->lock);  in crtc_crc_read()
302 		if (filep->f_flags & O_NONBLOCK) {  in crtc_crc_read()
303 			spin_unlock_irq(&crc->lock);  in crtc_crc_read()
304 			return -EAGAIN;  in crtc_crc_read()
307 		ret = wait_event_interruptible_lock_irq(crc->wq,  in crtc_crc_read()
309 							crc->lock);  in crtc_crc_read()
311 			spin_unlock_irq(&crc->lock);  in crtc_crc_read()
317 	entry = &crc->entries[crc->tail];  in crtc_crc_read()
319 	if (count < LINE_LEN(crc->values_cnt)) {  in crtc_crc_read()
320 		spin_unlock_irq(&crc->lock);  in crtc_crc_read()
321 		return -EINVAL;  in crtc_crc_read()
325 	crc->tail = (crc->tail + 1) & (DRM_CRC_ENTRIES_NR - 1);  in crtc_crc_read()
327 	spin_unlock_irq(&crc->lock);  in crtc_crc_read()
329 	if (entry->has_frame_counter)  in crtc_crc_read()
330 		sprintf(buf, "0x%08x", entry->frame);  in crtc_crc_read()
334 	for (i = 0; i < crc->values_cnt; i++)  in crtc_crc_read()
335 		sprintf(buf + 10 + i * 11, " 0x%08x", entry->crcs[i]);  in crtc_crc_read()
336 	sprintf(buf + 10 + crc->values_cnt * 11, "\n");  in crtc_crc_read()
338 	if (copy_to_user(user_buf, buf, LINE_LEN(crc->values_cnt)))  in crtc_crc_read()
339 		return -EFAULT;  in crtc_crc_read()
341 	return LINE_LEN(crc->values_cnt);  in crtc_crc_read()
346 	struct drm_crtc *crtc = file->f_inode->i_private;  in crtc_crc_poll()
347 	struct drm_crtc_crc *crc = &crtc->crc;  in crtc_crc_poll()
350 	poll_wait(file, &crc->wq, wait);  in crtc_crc_poll()
352 	spin_lock_irq(&crc->lock);  in crtc_crc_poll()
353 	if (crc->source && crtc_crc_data_count(crc))  in crtc_crc_poll()
355 	spin_unlock_irq(&crc->lock);  in crtc_crc_poll()
372 	if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source)  in drm_debugfs_crtc_crc_add()
375 	crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);  in drm_debugfs_crtc_crc_add()
384  * drm_crtc_add_crc_entry - Add entry with CRC information for a frame
385  * @crtc: CRTC to which the frame belongs
386  * @has_frame: whether this entry has a frame number to go with
387  * @frame: number of the frame these CRCs are about
390  * For each frame, the driver polls the source of CRCs for new data and calls
394 			   uint32_t frame, uint32_t *crcs)  in drm_crtc_add_crc_entry()  argument
396 	struct drm_crtc_crc *crc = &crtc->crc;  in drm_crtc_add_crc_entry()
401 	spin_lock_irqsave(&crc->lock, flags);  in drm_crtc_add_crc_entry()
404 	if (!crc->entries) {  in drm_crtc_add_crc_entry()
405 		spin_unlock_irqrestore(&crc->lock, flags);  in drm_crtc_add_crc_entry()
406 		return -EINVAL;  in drm_crtc_add_crc_entry()
409 	head = crc->head;  in drm_crtc_add_crc_entry()
410 	tail = crc->tail;  in drm_crtc_add_crc_entry()
413 		bool was_overflow = crc->overflow;  in drm_crtc_add_crc_entry()
415 		crc->overflow = true;  in drm_crtc_add_crc_entry()
416 		spin_unlock_irqrestore(&crc->lock, flags);  in drm_crtc_add_crc_entry()
421 		return -ENOBUFS;  in drm_crtc_add_crc_entry()
424 	entry = &crc->entries[head];  in drm_crtc_add_crc_entry()
425 	entry->frame = frame;  in drm_crtc_add_crc_entry()
426 	entry->has_frame_counter = has_frame;  in drm_crtc_add_crc_entry()
427 	memcpy(&entry->crcs, crcs, sizeof(*crcs) * crc->values_cnt);  in drm_crtc_add_crc_entry()
429 	head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);  in drm_crtc_add_crc_entry()
430 	crc->head = head;  in drm_crtc_add_crc_entry()
432 	spin_unlock_irqrestore(&crc->lock, flags);  in drm_crtc_add_crc_entry()
434 	wake_up_interruptible(&crc->wq);  in drm_crtc_add_crc_entry()