backend/drm: fetch EDID manufacturer from udev_hwdb

Maintaining our internal table up-to-date is tedious: one needs to
manually go through the PnP ID registry [1] and check whether we're
missing any entry.

udev_hwdb already has an API to fetch a manufacturer name from its
PnP ID. Use that instead.

[1]: https://uefi.org/pnp_id_list

backend/drm/backend.c

@@ -1,6 +1,7 @@
 #include <assert.h>
 #include <errno.h>
 #include <drm_fourcc.h>
+#include <libudev.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -58,6 +59,7 @@ static void backend_destroy(struct wlr_backend *backend) {
 
 	finish_drm_resources(drm);
 
+	udev_hwdb_unref(drm->hwdb);
 	free(drm->name);
 	wlr_session_close_file(drm->session, drm->dev);
 	wl_event_source_remove(drm->drm_event);
@@ -172,6 +174,23 @@ static void handle_parent_destroy(struct wl_listener *listener, void *data) {
 	backend_destroy(&drm->backend);
 }
 
+static struct udev_hwdb *create_udev_hwdb(void) {
+	struct udev *udev = udev_new();
+	if (!udev) {
+		wlr_log(WLR_ERROR, "udev_new failed");
+		return NULL;
+	}
+
+	struct udev_hwdb *hwdb = udev_hwdb_new(udev);
+	udev_unref(udev);
+	if (!hwdb) {
+		wlr_log(WLR_ERROR, "udev_hwdb_new failed");
+		return NULL;
+	}
+
+	return hwdb;
+}
+
 struct wlr_backend *wlr_drm_backend_create(struct wl_display *display,
 		struct wlr_session *session, struct wlr_device *dev,
 		struct wlr_backend *parent) {
@@ -226,6 +245,12 @@ struct wlr_backend *wlr_drm_backend_create(struct wl_display *display,
 	drm->session_active.notify = handle_session_active;
 	wl_signal_add(&session->events.active, &drm->session_active);
 
+	drm->hwdb = create_udev_hwdb();
+	if (!drm->hwdb) {
+		wlr_log(WLR_INFO, "Failed to load udev_hwdb, "
+			"falling back to PnP IDs instead of manufacturer names");
+	}
+
 	if (!check_drm_features(drm)) {
 		goto error_event;
 	}
@@ -275,6 +300,7 @@ error_mgpu_renderer:
 error_resources:
 	finish_drm_resources(drm);
 error_event:
+	udev_hwdb_unref(drm->hwdb);
 	wl_list_remove(&drm->session_active.link);
 	wl_event_source_remove(drm->drm_event);
 error_fd:

backend/drm/drm.c

@@ -1314,7 +1314,7 @@ void scan_drm_connectors(struct wlr_drm_backend *drm,
 			size_t edid_len = 0;
 			uint8_t *edid = get_drm_prop_blob(drm->fd,
 				wlr_conn->id, wlr_conn->props.edid, &edid_len);
-			parse_edid(&wlr_conn->output, edid_len, edid);
+			parse_edid(wlr_conn, edid_len, edid);
 			free(edid);
 
 			char *subconnector = NULL;

backend/drm/util.c

@@ -2,9 +2,11 @@
 #include <drm_fourcc.h>
 #include <drm_mode.h>
 #include <drm.h>
+#include <libudev.h>
 #include <stdio.h>
 #include <string.h>
 #include <wlr/util/log.h>
+#include "backend/drm/drm.h"
 #include "backend/drm/util.h"
 
 int32_t calculate_refresh_rate(const drmModeModeInfo *mode) {
@@ -26,94 +28,51 @@ int32_t calculate_refresh_rate(const drmModeModeInfo *mode) {
 	return refresh;
 }
 
-// Constructed from http://edid.tv/manufacturer
+static const char *get_manufacturer(struct udev_hwdb *hwdb, uint16_t code) {
-static const char *get_manufacturer(uint16_t id) {
+	static char pnp_id[4];
-#define ID(a, b, c) ((a & 0x1f) << 10) | ((b & 0x1f) << 5) | (c & 0x1f)
+
-	switch (id) {
+	// The ASCII 3-letter manufacturer PnP ID is encoded in 5-bit codes
-	case ID('A', 'A', 'A'): return "Avolites Ltd";
+	pnp_id[0] = ((code >> 10) & 0x1F) + '@';
-	case ID('A', 'C', 'I'): return "Ancor Communications Inc";
+	pnp_id[1] = ((code >> 5) & 0x1F) + '@';
-	case ID('A', 'C', 'R'): return "Acer Technologies";
+	pnp_id[2] = ((code >> 0) & 0x1F) + '@';
-	case ID('A', 'D', 'A'): return "Addi-Data GmbH";
+	pnp_id[3] = '\0';
-	case ID('A', 'P', 'P'): return "Apple Computer Inc";
+
-	case ID('A', 'S', 'K'): return "Ask A/S";
+	if (hwdb == NULL) {
-	case ID('A', 'V', 'T'): return "Avtek (Electronics) Pty Ltd";
+		return pnp_id;
-	case ID('B', 'N', 'O'): return "Bang & Olufsen";
-	case ID('B', 'N', 'Q'): return "BenQ Corporation";
-	case ID('C', 'M', 'N'): return "Chimei Innolux Corporation";
-	case ID('C', 'M', 'O'): return "Chi Mei Optoelectronics corp.";
-	case ID('C', 'R', 'O'): return "Extraordinary Technologies PTY Limited";
-	case ID('D', 'E', 'L'): return "Dell Inc.";
-	case ID('D', 'G', 'C'): return "Data General Corporation";
-	case ID('D', 'O', 'N'): return "DENON, Ltd.";
-	case ID('E', 'N', 'C'): return "Eizo Nanao Corporation";
-	case ID('E', 'P', 'H'): return "Epiphan Systems Inc.";
-	case ID('E', 'X', 'P'): return "Data Export Corporation";
-	case ID('F', 'N', 'I'): return "Funai Electric Co., Ltd.";
-	case ID('F', 'U', 'S'): return "Fujitsu Siemens Computers GmbH";
-	case ID('G', 'S', 'M'): return "Goldstar Company Ltd";
-	case ID('H', 'I', 'Q'): return "Kaohsiung Opto Electronics Americas, Inc.";
-	case ID('H', 'S', 'D'): return "HannStar Display Corp";
-	case ID('H', 'T', 'C'): return "Hitachi Ltd";
-	case ID('H', 'W', 'P'): return "Hewlett Packard";
-	case ID('I', 'N', 'T'): return "Interphase Corporation";
-	case ID('I', 'N', 'X'): return "Communications Supply Corporation (A division of WESCO)";
-	case ID('I', 'T', 'E'): return "Integrated Tech Express Inc";
-	case ID('I', 'V', 'M'): return "Iiyama North America";
-	case ID('L', 'E', 'N'): return "Lenovo Group Limited";
-	case ID('M', 'A', 'X'): return "Rogen Tech Distribution Inc";
-	case ID('M', 'E', 'G'): return "Abeam Tech Ltd";
-	case ID('M', 'E', 'I'): return "Panasonic Industry Company";
-	case ID('M', 'T', 'C'): return "Mars-Tech Corporation";
-	case ID('M', 'T', 'X'): return "Matrox";
-	case ID('N', 'E', 'C'): return "NEC Corporation";
-	case ID('N', 'E', 'X'): return "Nexgen Mediatech Inc.";
-	case ID('O', 'N', 'K'): return "ONKYO Corporation";
-	case ID('O', 'R', 'N'): return "ORION ELECTRIC CO., LTD.";
-	case ID('O', 'T', 'M'): return "Optoma Corporation";
-	case ID('O', 'V', 'R'): return "Oculus VR, Inc.";
-	case ID('P', 'H', 'L'): return "Philips Consumer Electronics Company";
-	case ID('P', 'I', 'O'): return "Pioneer Electronic Corporation";
-	case ID('P', 'N', 'R'): return "Planar Systems, Inc.";
-	case ID('Q', 'D', 'S'): return "Quanta Display Inc.";
-	case ID('R', 'A', 'T'): return "Rent-A-Tech";
-	case ID('R', 'E', 'N'): return "Renesas Technology Corp.";
-	case ID('S', 'A', 'M'): return "Samsung Electric Company";
-	case ID('S', 'A', 'N'): return "Sanyo Electric Co., Ltd.";
-	case ID('S', 'E', 'C'): return "Seiko Epson Corporation";
-	case ID('S', 'H', 'P'): return "Sharp Corporation";
-	case ID('S', 'I', 'I'): return "Silicon Image, Inc.";
-	case ID('S', 'N', 'Y'): return "Sony";
-	case ID('S', 'T', 'D'): return "STD Computer Inc";
-	case ID('S', 'V', 'S'): return "SVSI";
-	case ID('S', 'Y', 'N'): return "Synaptics Inc";
-	case ID('T', 'C', 'L'): return "Technical Concepts Ltd";
-	case ID('T', 'O', 'P'): return "Orion Communications Co., Ltd.";
-	case ID('T', 'S', 'B'): return "Toshiba America Info Systems Inc";
-	case ID('T', 'S', 'T'): return "Transtream Inc";
-	case ID('U', 'N', 'K'): return "Unknown";
-	case ID('V', 'E', 'S'): return "Vestel Elektronik Sanayi ve Ticaret A. S.";
-	case ID('V', 'I', 'T'): return "Visitech AS";
-	case ID('V', 'I', 'Z'): return "VIZIO, Inc";
-	case ID('V', 'L', 'V'): return "Valve";
-	case ID('V', 'S', 'C'): return "ViewSonic Corporation";
-	case ID('Y', 'M', 'H'): return "Yamaha Corporation";
-	default:                return "Unknown";
 	}
-#undef ID
+
+	char query[32];
+	snprintf(query, sizeof(query), "acpi:%s:", pnp_id);
+	struct udev_list_entry *acpi_entry =
+		udev_hwdb_get_properties_list_entry(hwdb, query, 0);
+	if (acpi_entry == NULL) {
+		return pnp_id;
+	}
+
+	struct udev_list_entry *vendor_entry =
+		udev_list_entry_get_by_name(acpi_entry, "ID_VENDOR_FROM_DATABASE");
+	if (vendor_entry == NULL) {
+		return pnp_id;
+	}
+
+	return udev_list_entry_get_value(vendor_entry);
 }
 
 /* See https://en.wikipedia.org/wiki/Extended_Display_Identification_Data for layout of EDID data.
  * We don't parse the EDID properly. We just expect to receive valid data.
  */
-void parse_edid(struct wlr_output *restrict output, size_t len, const uint8_t *data) {
+void parse_edid(struct wlr_drm_connector *conn, size_t len, const uint8_t *data) {
+	struct wlr_output *output = &conn->output;
+
 	if (!data || len < 128) {
-		snprintf(output->make, sizeof(output->make), "<Unknown>");
+		snprintf(output->make, sizeof(output->make), "Unknown");
-		snprintf(output->model, sizeof(output->model), "<Unknown>");
+		snprintf(output->model, sizeof(output->model), "Unknown");
 		return;
 	}
 
 	uint16_t id = (data[8] << 8) | data[9];
-	snprintf(output->make, sizeof(output->make), "%s", get_manufacturer(id));
+	snprintf(output->make, sizeof(output->make), "%s",
+		get_manufacturer(conn->backend->hwdb, id));
 
 	uint16_t model = data[10] | (data[11] << 8);
 	snprintf(output->model, sizeof(output->model), "0x%04X", model);

include/backend/drm/drm.h

@@ -58,6 +58,7 @@ struct wlr_drm_backend {
 	const struct wlr_drm_interface *iface;
 	clockid_t clock;
 	bool addfb2_modifiers;
+	struct udev_hwdb *hwdb;
 
 	int fd;
 	char *name;

include/backend/drm/util.h

@@ -2,15 +2,15 @@
 #define BACKEND_DRM_UTIL_H
 
 #include <stdint.h>
-#include <wlr/types/wlr_output.h>
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 
+struct wlr_drm_connector;
+
 // Calculates a more accurate refresh rate (mHz) than what mode itself provides
 int32_t calculate_refresh_rate(const drmModeModeInfo *mode);
 // Populates the make/model/phys_{width,height} of output from the edid data
-void parse_edid(struct wlr_output *restrict output, size_t len,
+void parse_edid(struct wlr_drm_connector *conn, size_t len, const uint8_t *data);
-	const uint8_t *data);
 // Returns the string representation of a DRM output type
 const char *conn_get_name(uint32_t type_id);