Re: [PATCH v2 3/5] drm/modes: Allow to specify rotation and reflection on the commandline

["Noralf Trønnes" <noralf@tronnes.org>]

Den 11.04.2019 15.22, skrev Maxime Ripard:
> Rotations and reflections setup are needed in some scenarios to initialise
> properly the initial framebuffer. Some drivers already had a bunch of
> quirks to deal with this, such as either a private kernel command line
> parameter (omapdss) or on the device tree (various panels).
> 
> In order to accomodate this, let's create a video mode parameter to deal
> with the rotation and reflexion.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
>  drivers/gpu/drm/drm_fb_helper.c |   4 +-
>  drivers/gpu/drm/drm_modes.c     | 110 +++++++++++++++++++++++++++------
>  include/drm/drm_connector.h     |   1 +-
>  3 files changed, 95 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index b3a5d79436ae..8781897559b2 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -2521,6 +2521,7 @@ static void drm_setup_crtc_rotation(struct drm_fb_helper *fb_helper,
>  				    struct drm_connector *connector)
>  {
>  	struct drm_plane *plane = fb_crtc->mode_set.crtc->primary;
> +	struct drm_cmdline_mode *mode = &connector->cmdline_mode;
>  	uint64_t valid_mask = 0;
>  	int i, rotation;
>  
> @@ -2540,6 +2541,9 @@ static void drm_setup_crtc_rotation(struct drm_fb_helper *fb_helper,
>  		rotation = DRM_MODE_ROTATE_0;
>  	}
>  
> +	if (mode->rotation != DRM_MODE_ROTATE_0)
> +		fb_crtc->rotation = mode->rotation;
> +

We already have a property to describe initial display/panel rotation.
If we can set connector->display_info.panel_orientation from the video=
parameter, then there's no need to modify drm_fb_helper, it will just work.

In that case, maybe 'orientation' is a better argument name with values
mapped to the enum.

And further, should we add the property
(drm_connector_init_panel_orientation_property()) so DRM userspace can
know about it to?

Some pointers:
- 8d70f395e6cb ("drm: Add support for a panel-orientation connector
property")
- 8f0cb418393b ("drm/fb-helper: Apply panel orientation connector prop
to the primary plane")
- drivers/gpu/drm/drm_panel_orientation_quirks.c

Noralf.

>  	/*
>  	 * TODO: support 90 / 270 degree hardware rotation,
>  	 * depending on the hardware this may require the framebuffer
> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> index 9613c1a28487..ac8d70b92b62 100644
> --- a/drivers/gpu/drm/drm_modes.c
> +++ b/drivers/gpu/drm/drm_modes.c
> @@ -1531,6 +1531,71 @@ static int drm_mode_parse_cmdline_res_mode(const char *str, unsigned int length,
>  	return 0;
>  }
>  
> +static int drm_mode_parse_cmdline_options(char *str, size_t len,
> +					  struct drm_connector *connector,
> +					  struct drm_cmdline_mode *mode)
> +{
> +	unsigned int rotation = 0;
> +	char *sep = str;
> +
> +	while ((sep = strchr(sep, ','))) {
> +		char *delim, *option;
> +
> +		option = sep + 1;
> +		delim = strchr(option, '=');
> +		if (!delim) {
> +			delim = strchr(option, ',');
> +
> +			if (!delim)
> +				delim = str + len;
> +		}
> +
> +		if (!strncmp(option, "rotate", delim - option)) {
> +			const char *value = delim + 1;
> +			unsigned int deg;
> +
> +			deg = simple_strtol(value, &sep, 10);
> +
> +			/* Make sure we have parsed something */
> +			if (sep == value)
> +				return -EINVAL;
> +
> +			switch (deg) {
> +			case 0:
> +				rotation |= DRM_MODE_ROTATE_0;
> +				break;
> +
> +			case 90:
> +				rotation |= DRM_MODE_ROTATE_90;
> +				break;
> +
> +			case 180:
> +				rotation |= DRM_MODE_ROTATE_180;
> +				break;
> +
> +			case 270:
> +				rotation |= DRM_MODE_ROTATE_270;
> +				break;
> +
> +			default:
> +				return -EINVAL;
> +			}
> +		} else if (!strncmp(option, "reflect_x", delim - option)) {
> +			rotation |= DRM_MODE_REFLECT_X;
> +			sep = delim;
> +		} else if (!strncmp(option, "reflect_y", delim - option)) {
> +			rotation |= DRM_MODE_REFLECT_Y;
> +			sep = delim;
> +		} else {
> +			return -EINVAL;
> +		}
> +	}
> +
> +	mode->rotation = rotation;
> +
> +	return 0;
> +}
> +
>  /**
>   * drm_mode_parse_command_line_for_connector - parse command line modeline for connector
>   * @mode_option: optional per connector mode option
> @@ -1558,9 +1623,10 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
>  {
>  	const char *name;
>  	bool named_mode = false, parse_extras = false;
> -	unsigned int bpp_off = 0, refresh_off = 0;
> +	unsigned int bpp_off = 0, refresh_off = 0, options_off = 0;
>  	unsigned int mode_end = 0;
>  	char *bpp_ptr = NULL, *refresh_ptr = NULL, *extra_ptr = NULL;
> +	char *options_ptr = NULL;
>  	char *bpp_end_ptr = NULL, *refresh_end_ptr = NULL;
>  	int ret;
>  
> @@ -1601,13 +1667,18 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
>  		mode->refresh_specified = true;
>  	}
>  
> +	/* Locate the start of named options */
> +	options_ptr = strchr(name, ',');
> +	if (options_ptr)
> +		options_off = options_ptr - name;
> +
>  	/* 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) {
> +	if (bpp_ptr) {
>  		mode_end = bpp_off;
>  	} else if (refresh_ptr) {
>  		mode_end = refresh_off;
> +	} else if (options_ptr) {
> +		mode_end = options_off;
>  	} else {
>  		mode_end = strlen(name);
>  		parse_extras = true;
> @@ -1649,24 +1720,23 @@ bool drm_mode_parse_command_line_for_connector(const char *mode_option,
>  	else if (refresh_ptr)
>  		extra_ptr = refresh_end_ptr;
>  
> -	if (extra_ptr) {
> -		if (!named_mode) {
> -			int len = strlen(name) - (extra_ptr - name);
> +	if (extra_ptr &&
> +	    extra_ptr != options_ptr) {
> +		int len = strlen(name) - (extra_ptr - name);
>  
> -			ret = drm_mode_parse_cmdline_extra(extra_ptr, len,
> -							   connector, mode);
> -			if (ret)
> -				return false;
> -		} else {
> -			int remaining = strlen(name) - (extra_ptr - name);
> +		ret = drm_mode_parse_cmdline_extra(extra_ptr, len,
> +						   connector, mode);
> +		if (ret)
> +			return false;
> +	}
>  
> -			/*
> -			 * We still have characters to process, while
> -			 * we shouldn't have any
> -			 */
> -			if (remaining > 0)
> -				return false;
> -		}
> +	if (options_ptr) {
> +		int len = strlen(name) - (options_ptr - name);
> +
> +		ret = drm_mode_parse_cmdline_options(options_ptr, len,
> +						     connector, mode);
> +		if (ret)
> +			return false;
>  	}
>  
>  	return true;
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 06aa3b9cb920..dfe7f2304b35 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -907,6 +907,7 @@ struct drm_cmdline_mode {
>  	bool interlace;
>  	bool cvt;
>  	bool margins;
> +	unsigned int rotation;
>  	enum drm_connector_force force;
>  };
>  
> 

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