Re: [PATCH v5 07/12] drm/modes: Allow to specify rotation and reflection on the commandline

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

Den 17.06.2019 16.51, 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>
> ---
>  Documentation/fb/modedb.rst          |  11 +++-
>  drivers/gpu/drm/drm_client_modeset.c |  30 +++++++-
>  drivers/gpu/drm/drm_modes.c          | 114 +++++++++++++++++++++++-----
>  include/drm/drm_connector.h          |  10 ++-
>  4 files changed, 145 insertions(+), 20 deletions(-)
> 
> diff --git a/Documentation/fb/modedb.rst b/Documentation/fb/modedb.rst
> index 3c2397293977..3e8a6f79dcd7 100644
> --- a/Documentation/fb/modedb.rst
> +++ b/Documentation/fb/modedb.rst
> @@ -53,6 +53,17 @@ Specifying the option multiple times for different ports is possible, e.g.::
>  
>      video=LVDS-1:d video=HDMI-1:D
>  
> +Options can also be passed after the mode, using commas as separator.
> +
> +       Sample usage: 720x480,rotate=180 - 720x480 mode, rotated by 180 degrees
> +
> +Valid options are:
> +
> +  - reflect_x (boolean): Perform an axial symetry on the X axis
> +  - reflect_y (boolean): Perform an axial symetry on the Y axis

2x s/symetry/symmetry/

Reviewed-by: Noralf Trønnes <noralf@tronnes.org>

> +  - rotate (integer): Rotate the initial framebuffer by x
> +    degrees. Valid values are 0, 90, 180 and 270.
> +
>  -----------------------------------------------------------------------------
>  
>  What is the VESA(TM) Coordinated Video Timings (CVT)?
> diff --git a/drivers/gpu/drm/drm_client_modeset.c b/drivers/gpu/drm/drm_client_modeset.c
> index 33d4988f22ae..e95fceac8f8b 100644
> --- a/drivers/gpu/drm/drm_client_modeset.c
> +++ b/drivers/gpu/drm/drm_client_modeset.c
> @@ -824,6 +824,7 @@ bool drm_client_rotation(struct drm_mode_set *modeset, unsigned int *rotation)
>  {
>  	struct drm_connector *connector = modeset->connectors[0];
>  	struct drm_plane *plane = modeset->crtc->primary;
> +	struct drm_cmdline_mode *cmdline;
>  	u64 valid_mask = 0;
>  	unsigned int i;
>  
> @@ -844,6 +845,35 @@ bool drm_client_rotation(struct drm_mode_set *modeset, unsigned int *rotation)
>  		*rotation = DRM_MODE_ROTATE_0;
>  	}
>  
> +	/**
> +	 * The panel already defined the default rotation
> +	 * through its orientation. Whatever has been provided
> +	 * on the command line needs to be added to that.
> +	 *
> +	 * Unfortunately, the rotations are at different bit
> +	 * indices, so the math to add them up are not as
> +	 * trivial as they could.
> +	 *
> +	 * Reflections on the other hand are pretty trivial to deal with, a
> +	 * simple XOR between the two handle the addition nicely.
> +	 */
> +	cmdline = &connector->cmdline_mode;
> +	if (cmdline->specified) {
> +		unsigned int cmdline_rest, panel_rest;
> +		unsigned int cmdline_rot, panel_rot;
> +		unsigned int sum_rot, sum_rest;
> +
> +		panel_rot = ilog2(*rotation & DRM_MODE_ROTATE_MASK);
> +		cmdline_rot = ilog2(cmdline->rotation_reflection & DRM_MODE_ROTATE_MASK);
> +		sum_rot = (panel_rot + cmdline_rot) % 4;
> +
> +		panel_rest = *rotation & ~DRM_MODE_ROTATE_MASK;
> +		cmdline_rest = cmdline->rotation_reflection & ~DRM_MODE_ROTATE_MASK;
> +		sum_rest = panel_rest ^ cmdline_rest;
> +
> +		*rotation = (1 << sum_rot) | sum_rest;
> +	}
> +
>  	/*
>  	 * 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 429d3be17800..dc6d11292685 100644
> --- a/drivers/gpu/drm/drm_modes.c
> +++ b/drivers/gpu/drm/drm_modes.c
> @@ -1554,6 +1554,71 @@ 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_reflection = rotation;
> +
> +	return 0;
> +}
> +
>  /**
>   * drm_mode_parse_command_line_for_connector - parse command line modeline for connector
>   * @mode_option: optional per connector mode option
> @@ -1569,6 +1634,10 @@ static int drm_mode_parse_cmdline_res_mode(const char *str, unsigned int length,
>   *
>   *	<xres>x<yres>[M][R][-<bpp>][@<refresh>][i][m][eDd]
>   *
> + * Additionals options can be provided following the mode, using a comma to
> + * separate each option. Valid options can be found in
> + * Documentation/fb/modedb.txt.
> + *
>   * The intermediate drm_cmdline_mode structure is required to store additional
>   * options from the command line modline like the force-enable/disable flag.
>   *
> @@ -1581,9 +1650,10 @@ 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;
>  
> @@ -1632,13 +1702,18 @@ 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;
> @@ -1680,24 +1755,23 @@ 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 cdf2fb910010..8eebe0432c73 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -1025,6 +1025,16 @@ struct drm_cmdline_mode {
>  	 * state to one of the DRM_FORCE_* values.
>  	 */
>  	enum drm_connector_force force;
> +
> +	/**
> +	 * @rotation_reflection:
> +	 *
> +	 * Initial rotation and reflection of the mode setup from the
> +	 * command line. See DRM_MODE_ROTATE_* and
> +	 * DRM_MODE_REFLECT_*. The only rotations supported are
> +	 * DRM_MODE_ROTATE_0 and DRM_MODE_ROTATE_180.
> +	 */
> +	unsigned int rotation_reflection;
>  };
>  
>  /**
> 

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