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Message-ID: <CAOw6vbKf3B2DYJA-kpmxa7vLzRcv5LhyVtToPyB2d6-thdt4Ng@mail.gmail.com>
Date: Wed, 16 Nov 2016 12:12:53 -0500
From: Sean Paul <seanpaul@...omium.org>
To: Maxime Ripard <maxime.ripard@...e-electrons.com>
Cc: Daniel Vetter <daniel.vetter@...el.com>,
David Airlie <airlied@...ux.ie>,
dri-devel <dri-devel@...ts.freedesktop.org>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Boris Brezillon <boris.brezillon@...e-electrons.com>,
Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
Linux ARM Kernel <linux-arm-kernel@...ts.infradead.org>,
Hans de Goede <hdegoede@...hat.com>,
Chen-Yu Tsai <wens@...e.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/5] drm/modes: Rewrite the command line parser
On Tue, Oct 18, 2016 at 4:29 AM, Maxime Ripard
<maxime.ripard@...e-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@...e-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
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