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

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;
  

}

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