From 2cea4924c69b6be5cfe8d976810ccf76a3991230 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime.ripard@bootlin.com>
Date: Wed, 19 Jun 2019 12:17:50 +0200
Subject: [PATCH] drm/modes: Support modes names on the command line
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 3aeeb13d899627fe2b86bdbdcd0927cf7192234f upstream.
Minor conflict resolution as upstream has moved functions
from drm_fb_helper.c to a new drm_client_modeset.c

The drm subsystem also uses the video= kernel parameter, and in the
documentation refers to the fbdev documentation for that parameter.

However, that documentation also says that instead of giving the mode using
its resolution we can also give a name. However, DRM doesn't handle that
case at the moment. Even though in most case it shouldn't make any
difference, it might be useful for analog modes, where different standards
might have the same resolution, but still have a few different parameters
that are not encoded in the modes (NTSC vs NTSC-J vs PAL-M for example).

Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/18443e0c3bdbbd16cea4ec63bc7f2079b820b43b.1560783090.git-series.maxime.ripard@bootlin.com
---
 drivers/gpu/drm/drm_connector.c |  3 +-
 drivers/gpu/drm/drm_fb_helper.c |  4 +++
 drivers/gpu/drm/drm_modes.c     | 62 ++++++++++++++++++++++++---------
 include/drm/drm_connector.h     |  7 ++++
 4 files changed, 59 insertions(+), 17 deletions(-)

--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -135,8 +135,9 @@ static void drm_connector_get_cmdline_mo
 		connector->force = mode->force;
 	}
 
-	DRM_DEBUG_KMS("cmdline mode for connector %s %dx%d@%dHz%s%s%s\n",
+	DRM_DEBUG_KMS("cmdline mode for connector %s %s %dx%d@%dHz%s%s%s\n",
 		      connector->name,
+		      mode->name ? mode->name : "",
 		      mode->xres, mode->yres,
 		      mode->refresh_specified ? mode->refresh : 60,
 		      mode->rb ? " reduced blanking" : "",
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -2104,6 +2104,10 @@ struct drm_display_mode *drm_pick_cmdlin
 	prefer_non_interlace = !cmdline_mode->interlace;
 again:
 	list_for_each_entry(mode, &fb_helper_conn->connector->modes, head) {
+		/* Check (optional) mode name first */
+		if (!strcmp(mode->name, cmdline_mode->name))
+			return mode;
+
 		/* check width/height */
 		if (mode->hdisplay != cmdline_mode->xres ||
 		    mode->vdisplay != cmdline_mode->yres)
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -1586,7 +1586,7 @@ bool drm_mode_parse_command_line_for_con
 					       struct drm_cmdline_mode *mode)
 {
 	const char *name;
-	bool parse_extras = false;
+	bool named_mode = false, parse_extras = false;
 	unsigned int bpp_off = 0, refresh_off = 0;
 	unsigned int mode_end = 0;
 	char *bpp_ptr = NULL, *refresh_ptr = NULL, *extra_ptr = NULL;
@@ -1605,8 +1605,22 @@ bool drm_mode_parse_command_line_for_con
 
 	name = mode_option;
 
-	if (!isdigit(name[0]))
-		return false;
+	/*
+	 * This is a bit convoluted. To differentiate between the
+	 * named modes and poorly formatted resolutions, we need a
+	 * bunch of things:
+	 *   - We need to make sure that the first character (which
+	 *     would be our resolution in X) is a digit.
+	 *   - However, if the X resolution is missing, then we end up
+	 *     with something like x<yres>, with our first character
+	 *     being an alpha-numerical character, which would be
+	 *     considered a named mode.
+	 *
+	 * If this isn't enough, we should add more heuristics here,
+	 * and matching unit-tests.
+	 */
+	if (!isdigit(name[0]) && name[0] != 'x')
+		named_mode = true;
 
 	/* Try to locate the bpp and refresh specifiers, if any */
 	bpp_ptr = strchr(name, '-');
@@ -1617,6 +1631,9 @@ bool drm_mode_parse_command_line_for_con
 
 	refresh_ptr = strchr(name, '@');
 	if (refresh_ptr) {
+		if (named_mode)
+			return false;
+
 		refresh_off = refresh_ptr - name;
 		mode->refresh_specified = true;
 	}
@@ -1633,12 +1650,16 @@ bool drm_mode_parse_command_line_for_con
 		parse_extras = true;
 	}
 
-	ret = drm_mode_parse_cmdline_res_mode(name, mode_end,
-					      parse_extras,
-					      connector,
-					      mode);
-	if (ret)
-		return false;
+	if (named_mode) {
+		strncpy(mode->name, name, mode_end);
+	} else {
+		ret = drm_mode_parse_cmdline_res_mode(name, mode_end,
+						      parse_extras,
+						      connector,
+						      mode);
+		if (ret)
+			return false;
+	}
 	mode->specified = true;
 
 	if (bpp_ptr) {
@@ -1666,14 +1687,23 @@ bool drm_mode_parse_command_line_for_con
 		extra_ptr = refresh_end_ptr;
 
 	if (extra_ptr) {
-		int remaining = strlen(name) - (extra_ptr - name);
+		if (!named_mode) {
+			int len = strlen(name) - (extra_ptr - name);
 
-		/*
-		 * We still have characters to process, while
-		 * we shouldn't have any
-		 */
-		if (remaining > 0)
-			return false;
+			ret = drm_mode_parse_cmdline_extra(extra_ptr, len,
+							   connector, mode);
+			if (ret)
+				return false;
+		} else {
+			int remaining = strlen(name) - (extra_ptr - name);
+
+			/*
+			 * We still have characters to process, while
+			 * we shouldn't have any
+			 */
+			if (remaining > 0)
+				return false;
+		}
 	}
 
 	return true;
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -765,6 +765,13 @@ struct drm_connector_funcs {
  */
 struct drm_cmdline_mode {
 	/**
+	 * @name:
+	 *
+	 * Name of the mode.
+	 */
+	char name[DRM_DISPLAY_MODE_LEN];
+
+	/**
 	 * @specified:
 	 *
 	 * Has a mode been read from the command-line?