[PATCH v3 1/6] drm/modes: Rewrite the command line parser

Noralf Trønnes noralf at tronnes.org
Thu Apr 18 16:11:44 UTC 2019



Den 18.04.2019 14.41, skrev Maxime Ripard:
> From: Maxime Ripard <maxime.ripard at free-electrons.com>
> 
> 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 at 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 56f92a0bba62..3f89198f0891 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>
> @@ -1405,6 +1406,131 @@ void drm_connector_list_update(struct drm_connector *connector)
>  }
>  EXPORT_SYMBOL(drm_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);

What happens if this is not a number? I didn't find a test for that in
your unit tests. The same goes for _refresh().

> +	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')

'x600' looks to be a valid resolution here, so I think:
	if (str == end_ptr || 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;

Maybe some unit tests: '1024xy' and '1024x', to verify that this does
indeed require a number for yres.

Noralf.

> +
> +	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
> @@ -1431,13 +1557,12 @@ 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)
> @@ -1450,127 +1575,77 @@ 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;
>  }
> 


More information about the dri-devel mailing list