diff mbox

[1/5] drm/modes: Rewrite the command line parser

Message ID cf494b4e9585e720b2640705e3b2102c19d193c2.1476779323.git-series.maxime.ripard@free-electrons.com (mailing list archive)
State New, archived
Headers show

Commit Message

Maxime Ripard Oct. 18, 2016, 8:29 a.m. UTC
Rewrite the command line parser in order to get away from the state machine
parsing the video mode lines.

Hopefully, this will allow to extend it more easily to support named modes
and / or properties set directly on the command line.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 drivers/gpu/drm/drm_modes.c | 305 +++++++++++++++++++++++--------------
 1 file changed, 190 insertions(+), 115 deletions(-)

Comments

Sean Paul Nov. 16, 2016, 5:12 p.m. UTC | #1
On Tue, Oct 18, 2016 at 4:29 AM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:
> Rewrite the command line parser in order to get away from the state machine
> parsing the video mode lines.
>
> Hopefully, this will allow to extend it more easily to support named modes
> and / or properties set directly on the command line.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
>  drivers/gpu/drm/drm_modes.c | 305 +++++++++++++++++++++++--------------
>  1 file changed, 190 insertions(+), 115 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> index 53f07ac7c174..7d5bdca276f2 100644
> --- a/drivers/gpu/drm/drm_modes.c
> +++ b/drivers/gpu/drm/drm_modes.c
> @@ -30,6 +30,7 @@
>   * authorization from the copyright holder(s) and author(s).
>   */
>
> +#include <linux/ctype.h>
>  #include <linux/list.h>
>  #include <linux/list_sort.h>
>  #include <linux/export.h>
> @@ -1261,6 +1262,131 @@ void drm_mode_connector_list_update(struct drm_connector *connector)
>  }
>  EXPORT_SYMBOL(drm_mode_connector_list_update);
>
> +static int drm_mode_parse_cmdline_bpp(const char *str, char **end_ptr,
> +                                     struct drm_cmdline_mode *mode)
> +{
> +       if (str[0] != '-')
> +               return -EINVAL;
> +
> +       mode->bpp = simple_strtol(str + 1, end_ptr, 10);
> +       mode->bpp_specified = true;
> +
> +       return 0;
> +}
> +
> +static int drm_mode_parse_cmdline_refresh(const char *str, char **end_ptr,
> +                                         struct drm_cmdline_mode *mode)
> +{
> +       if (str[0] != '@')
> +               return -EINVAL;
> +
> +       mode->refresh = simple_strtol(str + 1, end_ptr, 10);
> +       mode->refresh_specified = true;
> +
> +       return 0;
> +}
> +
> +static int drm_mode_parse_cmdline_extra(const char *str, int length,
> +                                       struct drm_connector *connector,
> +                                       struct drm_cmdline_mode *mode)
> +{
> +       int i;
> +
> +       for (i = 0; i < length; i++) {
> +               switch (str[i]) {
> +               case 'i':
> +                       mode->interlace = true;
> +                       break;
> +               case 'm':
> +                       mode->margins = true;
> +                       break;
> +               case 'D':
> +                       if (mode->force != DRM_FORCE_UNSPECIFIED)
> +                               return -EINVAL;
> +
> +                       if ((connector->connector_type != DRM_MODE_CONNECTOR_DVII) &&
> +                           (connector->connector_type != DRM_MODE_CONNECTOR_HDMIB))
> +                               mode->force = DRM_FORCE_ON;
> +                       else
> +                               mode->force = DRM_FORCE_ON_DIGITAL;
> +                       break;
> +               case 'd':
> +                       if (mode->force != DRM_FORCE_UNSPECIFIED)
> +                               return -EINVAL;
> +
> +                       mode->force = DRM_FORCE_OFF;
> +                       break;
> +               case 'e':
> +                       if (mode->force != DRM_FORCE_UNSPECIFIED)
> +                               return -EINVAL;
> +
> +                       mode->force = DRM_FORCE_ON;
> +                       break;
> +               default:
> +                       return -EINVAL;
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +static int drm_mode_parse_cmdline_res_mode(const char *str, unsigned int length,
> +                                          bool extras,
> +                                          struct drm_connector *connector,
> +                                          struct drm_cmdline_mode *mode)
> +{
> +       bool rb = false, cvt = false;
> +       int xres = 0, yres = 0;
> +       int remaining, i;
> +       char *end_ptr;
> +
> +       xres = simple_strtol(str, &end_ptr, 10);
> +

checkpatch is telling me to use kstrtol instead, as simple_strtol is deprecated

> +       if (end_ptr[0] != 'x')

check that end_ptr != NULL? you should probably also check that xres
isn't an error (ie: -ERANGE or -EINVAL)

> +               return -EINVAL;
> +       end_ptr++;
> +
> +       yres = simple_strtol(end_ptr, &end_ptr, 10);

check end_ptr != NULL and yres sane

> +
> +       remaining = length - (end_ptr - str);
> +       if (remaining < 0)

right, so if end_ptr is NULL here, we'll end up with a huge positive
value for remaining :)

> +               return -EINVAL;
> +
> +       for (i = 0; i < remaining; i++) {
> +               switch (end_ptr[i]) {
> +               case 'M':
> +                       cvt = true;

the previous code ensured proper ordering as well as parsing, whereas
yours will take these in any order (and accepts duplicates). i don't
think this should cause any issues, but perhaps something to verify.

> +                       break;
> +               case 'R':
> +                       rb = true;
> +                       break;
> +               default:
> +                       /*
> +                        * Try to pass that to our extras parsing
> +                        * function to handle the case where the
> +                        * extras are directly after the resolution
> +                        */
> +                       if (extras) {
> +                               int ret = drm_mode_parse_cmdline_extra(end_ptr + i,
> +                                                                      1,
> +                                                                      connector,
> +                                                                      mode);
> +                               if (ret)
> +                                       return ret;
> +                       } else {
> +                               return -EINVAL;
> +                       }
> +               }
> +       }
> +
> +       mode->xres = xres;
> +       mode->yres = yres;
> +       mode->cvt = cvt;
> +       mode->rb = rb;
> +
> +       return 0;
> +}
> +
>  /**
>   * drm_mode_parse_command_line_for_connector - parse command line modeline for connector
>   * @mode_option: optional per connector mode option
> @@ -1287,13 +1413,12 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
>                                                struct drm_cmdline_mode *mode)
>  {
>         const char *name;
> -       unsigned int namelen;
> -       bool res_specified = false, bpp_specified = false, refresh_specified = false;
> -       unsigned int xres = 0, yres = 0, bpp = 32, refresh = 0;
> -       bool yres_specified = false, cvt = false, rb = false;
> -       bool interlace = false, margins = false, was_digit = false;
> -       int i;
> -       enum drm_connector_force force = DRM_FORCE_UNSPECIFIED;
> +       bool 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;
> +       char *bpp_end_ptr = NULL, *refresh_end_ptr = NULL;
> +       int ret;
>
>  #ifdef CONFIG_FB
>         if (!mode_option)
> @@ -1306,127 +1431,77 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
>         }
>
>         name = mode_option;
> -       namelen = strlen(name);
> -       for (i = namelen-1; i >= 0; i--) {
> -               switch (name[i]) {
> -               case '@':
> -                       if (!refresh_specified && !bpp_specified &&
> -                           !yres_specified && !cvt && !rb && was_digit) {
> -                               refresh = simple_strtol(&name[i+1], NULL, 10);
> -                               refresh_specified = true;
> -                               was_digit = false;
> -                       } else
> -                               goto done;
> -                       break;
> -               case '-':
> -                       if (!bpp_specified && !yres_specified && !cvt &&
> -                           !rb && was_digit) {
> -                               bpp = simple_strtol(&name[i+1], NULL, 10);
> -                               bpp_specified = true;
> -                               was_digit = false;
> -                       } else
> -                               goto done;
> -                       break;
> -               case 'x':
> -                       if (!yres_specified && was_digit) {
> -                               yres = simple_strtol(&name[i+1], NULL, 10);
> -                               yres_specified = true;
> -                               was_digit = false;
> -                       } else
> -                               goto done;
> -                       break;
> -               case '0' ... '9':
> -                       was_digit = true;
> -                       break;
> -               case 'M':
> -                       if (yres_specified || cvt || was_digit)
> -                               goto done;
> -                       cvt = true;
> -                       break;
> -               case 'R':
> -                       if (yres_specified || cvt || rb || was_digit)
> -                               goto done;
> -                       rb = true;
> -                       break;
> -               case 'm':
> -                       if (cvt || yres_specified || was_digit)
> -                               goto done;
> -                       margins = true;
> -                       break;
> -               case 'i':
> -                       if (cvt || yres_specified || was_digit)
> -                               goto done;
> -                       interlace = true;
> -                       break;
> -               case 'e':
> -                       if (yres_specified || bpp_specified || refresh_specified ||
> -                           was_digit || (force != DRM_FORCE_UNSPECIFIED))
> -                               goto done;
>
> -                       force = DRM_FORCE_ON;
> -                       break;
> -               case 'D':
> -                       if (yres_specified || bpp_specified || refresh_specified ||
> -                           was_digit || (force != DRM_FORCE_UNSPECIFIED))
> -                               goto done;
> +       if (!isdigit(name[0]))
> +               return false;
>
> -                       if ((connector->connector_type != DRM_MODE_CONNECTOR_DVII) &&
> -                           (connector->connector_type != DRM_MODE_CONNECTOR_HDMIB))
> -                               force = DRM_FORCE_ON;
> -                       else
> -                               force = DRM_FORCE_ON_DIGITAL;
> -                       break;
> -               case 'd':
> -                       if (yres_specified || bpp_specified || refresh_specified ||
> -                           was_digit || (force != DRM_FORCE_UNSPECIFIED))
> -                               goto done;
> +       /* Try to locate the bpp and refresh specifiers, if any */
> +       bpp_ptr = strchr(name, '-');
> +       if (bpp_ptr) {
> +               bpp_off = bpp_ptr - name;
> +               mode->bpp_specified = true;
> +       }
>
> -                       force = DRM_FORCE_OFF;
> -                       break;
> -               default:
> -                       goto done;
> -               }
> +       refresh_ptr = strchr(name, '@');
> +       if (refresh_ptr) {
> +               refresh_off = refresh_ptr - name;
> +               mode->refresh_specified = true;
>         }
>
> -       if (i < 0 && yres_specified) {
> -               char *ch;
> -               xres = simple_strtol(name, &ch, 10);
> -               if ((ch != NULL) && (*ch == 'x'))
> -                       res_specified = true;
> -               else
> -                       i = ch - name;
> -       } else if (!yres_specified && was_digit) {
> -               /* catch mode that begins with digits but has no 'x' */
> -               i = 0;
> +       /* Locate the end of the name / resolution, and parse it */
> +       if (bpp_ptr && refresh_ptr) {
> +               mode_end = min(bpp_off, refresh_off);
> +       } else if (bpp_ptr) {
> +               mode_end = bpp_off;
> +       } else if (refresh_ptr) {
> +               mode_end = refresh_off;
> +       } else {
> +               mode_end = strlen(name);
> +               parse_extras = true;
>         }
> -done:
> -       if (i >= 0) {
> -               pr_warn("[drm] parse error at position %i in video mode '%s'\n",
> -                       i, name);
> -               mode->specified = false;
> +
> +       ret = drm_mode_parse_cmdline_res_mode(name, mode_end,
> +                                             parse_extras,
> +                                             connector,
> +                                             mode);
> +       if (ret)
>                 return false;
> -       }
> +       mode->specified = true;
>
> -       if (res_specified) {
> -               mode->specified = true;
> -               mode->xres = xres;
> -               mode->yres = yres;
> +       if (bpp_ptr) {
> +               ret = drm_mode_parse_cmdline_bpp(bpp_ptr, &bpp_end_ptr, mode);
> +               if (ret)
> +                       return false;
>         }
>
> -       if (refresh_specified) {
> -               mode->refresh_specified = true;
> -               mode->refresh = refresh;
> +       if (refresh_ptr) {
> +               ret = drm_mode_parse_cmdline_refresh(refresh_ptr,
> +                                                    &refresh_end_ptr, mode);
> +               if (ret)
> +                       return false;
>         }
>
> -       if (bpp_specified) {
> -               mode->bpp_specified = true;
> -               mode->bpp = bpp;
> +       /*
> +        * Locate the end of the bpp / refresh, and parse the extras
> +        * if relevant
> +        */
> +       if (bpp_ptr && refresh_ptr)

Perhaps I'm paranoid, but I think it'd be better to check bpp_end_ptr
&& refresh_end_ptr in this conditional.

Sean

> +               extra_ptr = max(bpp_end_ptr, refresh_end_ptr);
> +       else if (bpp_ptr)
> +               extra_ptr = bpp_end_ptr;
> +       else if (refresh_ptr)
> +               extra_ptr = refresh_end_ptr;
> +
> +       if (extra_ptr) {
> +               int remaining = strlen(name) - (extra_ptr - name);
> +
> +               /*
> +                * We still have characters to process, while
> +                * we shouldn't have any
> +                */
> +               if (remaining > 0)
> +                       return false;
>         }
> -       mode->rb = rb;
> -       mode->cvt = cvt;
> -       mode->interlace = interlace;
> -       mode->margins = margins;
> -       mode->force = force;
>
>         return true;
>  }
> --
> git-series 0.8.10
Maxime Ripard Nov. 21, 2016, 7:36 a.m. UTC | #2
Hi Sean,

Thanks for taking the time to review this.

On Wed, Nov 16, 2016 at 12:12:53PM -0500, Sean Paul wrote:
> On Tue, Oct 18, 2016 at 4:29 AM, Maxime Ripard
> <maxime.ripard@free-electrons.com> wrote:
> > Rewrite the command line parser in order to get away from the state machine
> > parsing the video mode lines.
> >
> > Hopefully, this will allow to extend it more easily to support named modes
> > and / or properties set directly on the command line.
> >
> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > ---
> >  drivers/gpu/drm/drm_modes.c | 305 +++++++++++++++++++++++--------------
> >  1 file changed, 190 insertions(+), 115 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> > index 53f07ac7c174..7d5bdca276f2 100644
> > --- a/drivers/gpu/drm/drm_modes.c
> > +++ b/drivers/gpu/drm/drm_modes.c
> > @@ -30,6 +30,7 @@
> >   * authorization from the copyright holder(s) and author(s).
> >   */
> >
> > +#include <linux/ctype.h>
> >  #include <linux/list.h>
> >  #include <linux/list_sort.h>
> >  #include <linux/export.h>
> > @@ -1261,6 +1262,131 @@ void drm_mode_connector_list_update(struct drm_connector *connector)
> >  }
> >  EXPORT_SYMBOL(drm_mode_connector_list_update);
> >
> > +static int drm_mode_parse_cmdline_bpp(const char *str, char **end_ptr,
> > +                                     struct drm_cmdline_mode *mode)
> > +{
> > +       if (str[0] != '-')
> > +               return -EINVAL;
> > +
> > +       mode->bpp = simple_strtol(str + 1, end_ptr, 10);
> > +       mode->bpp_specified = true;
> > +
> > +       return 0;
> > +}
> > +
> > +static int drm_mode_parse_cmdline_refresh(const char *str, char **end_ptr,
> > +                                         struct drm_cmdline_mode *mode)
> > +{
> > +       if (str[0] != '@')
> > +               return -EINVAL;
> > +
> > +       mode->refresh = simple_strtol(str + 1, end_ptr, 10);
> > +       mode->refresh_specified = true;
> > +
> > +       return 0;
> > +}
> > +
> > +static int drm_mode_parse_cmdline_extra(const char *str, int length,
> > +                                       struct drm_connector *connector,
> > +                                       struct drm_cmdline_mode *mode)
> > +{
> > +       int i;
> > +
> > +       for (i = 0; i < length; i++) {
> > +               switch (str[i]) {
> > +               case 'i':
> > +                       mode->interlace = true;
> > +                       break;
> > +               case 'm':
> > +                       mode->margins = true;
> > +                       break;
> > +               case 'D':
> > +                       if (mode->force != DRM_FORCE_UNSPECIFIED)
> > +                               return -EINVAL;
> > +
> > +                       if ((connector->connector_type != DRM_MODE_CONNECTOR_DVII) &&
> > +                           (connector->connector_type != DRM_MODE_CONNECTOR_HDMIB))
> > +                               mode->force = DRM_FORCE_ON;
> > +                       else
> > +                               mode->force = DRM_FORCE_ON_DIGITAL;
> > +                       break;
> > +               case 'd':
> > +                       if (mode->force != DRM_FORCE_UNSPECIFIED)
> > +                               return -EINVAL;
> > +
> > +                       mode->force = DRM_FORCE_OFF;
> > +                       break;
> > +               case 'e':
> > +                       if (mode->force != DRM_FORCE_UNSPECIFIED)
> > +                               return -EINVAL;
> > +
> > +                       mode->force = DRM_FORCE_ON;
> > +                       break;
> > +               default:
> > +                       return -EINVAL;
> > +               }
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static int drm_mode_parse_cmdline_res_mode(const char *str, unsigned int length,
> > +                                          bool extras,
> > +                                          struct drm_connector *connector,
> > +                                          struct drm_cmdline_mode *mode)
> > +{
> > +       bool rb = false, cvt = false;
> > +       int xres = 0, yres = 0;
> > +       int remaining, i;
> > +       char *end_ptr;
> > +
> > +       xres = simple_strtol(str, &end_ptr, 10);
> > +
> 
> checkpatch is telling me to use kstrtol instead, as simple_strtol is deprecated
> 
> > +       if (end_ptr[0] != 'x')
> 
> check that end_ptr != NULL? you should probably also check that xres
> isn't an error (ie: -ERANGE or -EINVAL)
> 
> > +               return -EINVAL;
> > +       end_ptr++;
> > +
> > +       yres = simple_strtol(end_ptr, &end_ptr, 10);
> 
> check end_ptr != NULL and yres sane
> 
> > +
> > +       remaining = length - (end_ptr - str);
> > +       if (remaining < 0)
> 
> right, so if end_ptr is NULL here, we'll end up with a huge positive
> value for remaining :)
> 
> > +               return -EINVAL;
> > +
> > +       for (i = 0; i < remaining; i++) {
> > +               switch (end_ptr[i]) {
> > +               case 'M':
> > +                       cvt = true;
> 
> the previous code ensured proper ordering as well as parsing, whereas
> yours will take these in any order (and accepts duplicates). i don't
> think this should cause any issues, but perhaps something to verify.

Yes, I definitely overlooked the order of the parameters (and now I
get why the switch was so convoluted...)

I'll come up with a second version fixing that (and the other comments
you had).

Maxime
diff mbox

Patch

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 53f07ac7c174..7d5bdca276f2 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -30,6 +30,7 @@ 
  * authorization from the copyright holder(s) and author(s).
  */
 
+#include <linux/ctype.h>
 #include <linux/list.h>
 #include <linux/list_sort.h>
 #include <linux/export.h>
@@ -1261,6 +1262,131 @@  void drm_mode_connector_list_update(struct drm_connector *connector)
 }
 EXPORT_SYMBOL(drm_mode_connector_list_update);
 
+static int drm_mode_parse_cmdline_bpp(const char *str, char **end_ptr,
+				      struct drm_cmdline_mode *mode)
+{
+	if (str[0] != '-')
+		return -EINVAL;
+
+	mode->bpp = simple_strtol(str + 1, end_ptr, 10);
+	mode->bpp_specified = true;
+
+	return 0;
+}
+
+static int drm_mode_parse_cmdline_refresh(const char *str, char **end_ptr,
+					  struct drm_cmdline_mode *mode)
+{
+	if (str[0] != '@')
+		return -EINVAL;
+
+	mode->refresh = simple_strtol(str + 1, end_ptr, 10);
+	mode->refresh_specified = true;
+
+	return 0;
+}
+
+static int drm_mode_parse_cmdline_extra(const char *str, int length,
+					struct drm_connector *connector,
+					struct drm_cmdline_mode *mode)
+{
+	int i;
+
+	for (i = 0; i < length; i++) {
+		switch (str[i]) {
+		case 'i':
+			mode->interlace = true;
+			break;
+		case 'm':
+			mode->margins = true;
+			break;
+		case 'D':
+			if (mode->force != DRM_FORCE_UNSPECIFIED)
+				return -EINVAL;
+
+			if ((connector->connector_type != DRM_MODE_CONNECTOR_DVII) &&
+			    (connector->connector_type != DRM_MODE_CONNECTOR_HDMIB))
+				mode->force = DRM_FORCE_ON;
+			else
+				mode->force = DRM_FORCE_ON_DIGITAL;
+			break;
+		case 'd':
+			if (mode->force != DRM_FORCE_UNSPECIFIED)
+				return -EINVAL;
+
+			mode->force = DRM_FORCE_OFF;
+			break;
+		case 'e':
+			if (mode->force != DRM_FORCE_UNSPECIFIED)
+				return -EINVAL;
+
+			mode->force = DRM_FORCE_ON;
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int drm_mode_parse_cmdline_res_mode(const char *str, unsigned int length,
+					   bool extras,
+					   struct drm_connector *connector,
+					   struct drm_cmdline_mode *mode)
+{
+	bool rb = false, cvt = false;
+	int xres = 0, yres = 0;
+	int remaining, i;
+	char *end_ptr;
+
+	xres = simple_strtol(str, &end_ptr, 10);
+
+	if (end_ptr[0] != 'x')
+		return -EINVAL;
+	end_ptr++;
+
+	yres = simple_strtol(end_ptr, &end_ptr, 10);
+
+	remaining = length - (end_ptr - str);
+	if (remaining < 0)
+		return -EINVAL;
+
+	for (i = 0; i < remaining; i++) {
+		switch (end_ptr[i]) {
+		case 'M':
+			cvt = true;
+			break;
+		case 'R':
+			rb = true;
+			break;
+		default:
+			/*
+			 * Try to pass that to our extras parsing
+			 * function to handle the case where the
+			 * extras are directly after the resolution
+			 */
+			if (extras) {
+				int ret = drm_mode_parse_cmdline_extra(end_ptr + i,
+								       1,
+								       connector,
+								       mode);
+				if (ret)
+					return ret;
+			} else {
+				return -EINVAL;
+			}
+		}
+	}
+
+	mode->xres = xres;
+	mode->yres = yres;
+	mode->cvt = cvt;
+	mode->rb = rb;
+
+	return 0;
+}
+
 /**
  * drm_mode_parse_command_line_for_connector - parse command line modeline for connector
  * @mode_option: optional per connector mode option
@@ -1287,13 +1413,12 @@  bool drm_mode_parse_command_line_for_connector(const char *mode_option,
 					       struct drm_cmdline_mode *mode)
 {
 	const char *name;
-	unsigned int namelen;
-	bool res_specified = false, bpp_specified = false, refresh_specified = false;
-	unsigned int xres = 0, yres = 0, bpp = 32, refresh = 0;
-	bool yres_specified = false, cvt = false, rb = false;
-	bool interlace = false, margins = false, was_digit = false;
-	int i;
-	enum drm_connector_force force = DRM_FORCE_UNSPECIFIED;
+	bool 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;
+	char *bpp_end_ptr = NULL, *refresh_end_ptr = NULL;
+	int ret;
 
 #ifdef CONFIG_FB
 	if (!mode_option)
@@ -1306,127 +1431,77 @@  bool drm_mode_parse_command_line_for_connector(const char *mode_option,
 	}
 
 	name = mode_option;
-	namelen = strlen(name);
-	for (i = namelen-1; i >= 0; i--) {
-		switch (name[i]) {
-		case '@':
-			if (!refresh_specified && !bpp_specified &&
-			    !yres_specified && !cvt && !rb && was_digit) {
-				refresh = simple_strtol(&name[i+1], NULL, 10);
-				refresh_specified = true;
-				was_digit = false;
-			} else
-				goto done;
-			break;
-		case '-':
-			if (!bpp_specified && !yres_specified && !cvt &&
-			    !rb && was_digit) {
-				bpp = simple_strtol(&name[i+1], NULL, 10);
-				bpp_specified = true;
-				was_digit = false;
-			} else
-				goto done;
-			break;
-		case 'x':
-			if (!yres_specified && was_digit) {
-				yres = simple_strtol(&name[i+1], NULL, 10);
-				yres_specified = true;
-				was_digit = false;
-			} else
-				goto done;
-			break;
-		case '0' ... '9':
-			was_digit = true;
-			break;
-		case 'M':
-			if (yres_specified || cvt || was_digit)
-				goto done;
-			cvt = true;
-			break;
-		case 'R':
-			if (yres_specified || cvt || rb || was_digit)
-				goto done;
-			rb = true;
-			break;
-		case 'm':
-			if (cvt || yres_specified || was_digit)
-				goto done;
-			margins = true;
-			break;
-		case 'i':
-			if (cvt || yres_specified || was_digit)
-				goto done;
-			interlace = true;
-			break;
-		case 'e':
-			if (yres_specified || bpp_specified || refresh_specified ||
-			    was_digit || (force != DRM_FORCE_UNSPECIFIED))
-				goto done;
 
-			force = DRM_FORCE_ON;
-			break;
-		case 'D':
-			if (yres_specified || bpp_specified || refresh_specified ||
-			    was_digit || (force != DRM_FORCE_UNSPECIFIED))
-				goto done;
+	if (!isdigit(name[0]))
+		return false;
 
-			if ((connector->connector_type != DRM_MODE_CONNECTOR_DVII) &&
-			    (connector->connector_type != DRM_MODE_CONNECTOR_HDMIB))
-				force = DRM_FORCE_ON;
-			else
-				force = DRM_FORCE_ON_DIGITAL;
-			break;
-		case 'd':
-			if (yres_specified || bpp_specified || refresh_specified ||
-			    was_digit || (force != DRM_FORCE_UNSPECIFIED))
-				goto done;
+	/* Try to locate the bpp and refresh specifiers, if any */
+	bpp_ptr = strchr(name, '-');
+	if (bpp_ptr) {
+		bpp_off = bpp_ptr - name;
+		mode->bpp_specified = true;
+	}
 
-			force = DRM_FORCE_OFF;
-			break;
-		default:
-			goto done;
-		}
+	refresh_ptr = strchr(name, '@');
+	if (refresh_ptr) {
+		refresh_off = refresh_ptr - name;
+		mode->refresh_specified = true;
 	}
 
-	if (i < 0 && yres_specified) {
-		char *ch;
-		xres = simple_strtol(name, &ch, 10);
-		if ((ch != NULL) && (*ch == 'x'))
-			res_specified = true;
-		else
-			i = ch - name;
-	} else if (!yres_specified && was_digit) {
-		/* catch mode that begins with digits but has no 'x' */
-		i = 0;
+	/* Locate the end of the name / resolution, and parse it */
+	if (bpp_ptr && refresh_ptr) {
+		mode_end = min(bpp_off, refresh_off);
+	} else if (bpp_ptr) {
+		mode_end = bpp_off;
+	} else if (refresh_ptr) {
+		mode_end = refresh_off;
+	} else {
+		mode_end = strlen(name);
+		parse_extras = true;
 	}
-done:
-	if (i >= 0) {
-		pr_warn("[drm] parse error at position %i in video mode '%s'\n",
-			i, name);
-		mode->specified = false;
+
+	ret = drm_mode_parse_cmdline_res_mode(name, mode_end,
+					      parse_extras,
+					      connector,
+					      mode);
+	if (ret)
 		return false;
-	}
+	mode->specified = true;
 
-	if (res_specified) {
-		mode->specified = true;
-		mode->xres = xres;
-		mode->yres = yres;
+	if (bpp_ptr) {
+		ret = drm_mode_parse_cmdline_bpp(bpp_ptr, &bpp_end_ptr, mode);
+		if (ret)
+			return false;
 	}
 
-	if (refresh_specified) {
-		mode->refresh_specified = true;
-		mode->refresh = refresh;
+	if (refresh_ptr) {
+		ret = drm_mode_parse_cmdline_refresh(refresh_ptr,
+						     &refresh_end_ptr, mode);
+		if (ret)
+			return false;
 	}
 
-	if (bpp_specified) {
-		mode->bpp_specified = true;
-		mode->bpp = bpp;
+	/*
+	 * Locate the end of the bpp / refresh, and parse the extras
+	 * if relevant
+	 */
+	if (bpp_ptr && refresh_ptr)
+		extra_ptr = max(bpp_end_ptr, refresh_end_ptr);
+	else if (bpp_ptr)
+		extra_ptr = bpp_end_ptr;
+	else if (refresh_ptr)
+		extra_ptr = refresh_end_ptr;
+
+	if (extra_ptr) {
+		int remaining = strlen(name) - (extra_ptr - name);
+
+		/*
+		 * We still have characters to process, while
+		 * we shouldn't have any
+		 */
+		if (remaining > 0)
+			return false;
 	}
-	mode->rb = rb;
-	mode->cvt = cvt;
-	mode->interlace = interlace;
-	mode->margins = margins;
-	mode->force = force;
 
 	return true;
 }