drm/modes: Support modes names on the command line

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

diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
index 4869a0170bec19887dbf5c8b614ae001fcd28258..33d4988f22aeac48320f147cc273c4e1e81491cf 100644 (file)
--- a/drivers/gpu/drm/drm_client_modeset.c
+++ b/drivers/gpu/drm/drm_client_modeset.c
@@ -149,6 +149,10 @@ drm_connector_pick_cmdline_mode(struct drm_connector *connector)
        prefer_non_interlace = !cmdline_mode->interlace;
 again:
        list_for_each_entry(mode, &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)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 3ccdcf3dfcde27c0ee5b5d8b70a4d2af0ee8ca44..3afed5677946689758acafd640ef65ec7985f035 100644 (file)
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -139,8 +139,9 @@ static void drm_connector_get_cmdline_mode(struct drm_connector *connector)
                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" : "",

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 6debbd6c17636bb21794df8ac223534729b7a17d..429d3be17800f9d195970a773f6cda078a84f0ef 100644 (file)
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -1580,7 +1580,7 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
                                               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;
@@ -1599,8 +1599,22 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
 
        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, '-');
@@ -1611,6 +1625,9 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
 
        refresh_ptr = strchr(name, '@');
        if (refresh_ptr) {
+               if (named_mode)
+                       return false;
+
                refresh_off = refresh_ptr - name;
                mode->refresh_specified = true;
        }
@@ -1627,12 +1644,16 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
                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) {
@@ -1660,14 +1681,23 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
                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;

diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index c802780b0bfc8b7fb04637e635835db666dd1dc7..cdf2fb910010470d6601f43d239ff9b73f549812 100644 (file)
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -932,6 +932,13 @@ struct drm_connector_funcs {
  * parser.
  */
 struct drm_cmdline_mode {
+       /**
+        * @name:
+        *
+        * Name of the mode.
+        */
+       char name[DRM_DISPLAY_MODE_LEN];
+
        /**
         * @specified:
         *