drm/edid: add helper function to detect monitor audio capability (8fe9790d) · Commits · 戴 / test

drivers/gpu/drm/drm_edid.c

+78 −14

Original line number	Diff line number	Diff line
		@@ -1267,34 +1267,51 @@ add_detailed_modes(struct drm_connector connector, struct edid edid,
		}

		#define HDMI_IDENTIFIER 0x000C03
		#define AUDIO_BLOCK 0x01
		#define VENDOR_BLOCK 0x03
		#define EDID_BASIC_AUDIO (1 << 6)

		/**
		* drm_detect_hdmi_monitor - detect whether monitor is hdmi.
		* @edid: monitor EDID information
		*
		* Parse the CEA extension according to CEA-861-B.
		* Return true if HDMI, false if not or unknown.
		* Search EDID for CEA extension block.
		*/
		bool drm_detect_hdmi_monitor(struct edid *edid)
		static u8 drm_find_cea_extension(struct edid edid)
		{
		char *edid_ext = NULL;
		int i, hdmi_id;
		int start_offset, end_offset;
		bool is_hdmi = false;
		u8 *edid_ext = NULL;
		int i;

		/* No EDID or EDID extensions */
		if (edid == NULL \|\| edid->extensions == 0)
		goto end;
		return NULL;

		/* Find CEA extension */
		for (i = 0; i < edid->extensions; i++) {
		edid_ext = (char )edid + EDID_LENGTH (i + 1);
		/* This block is CEA extension */
		if (edid_ext[0] == 0x02)
		edid_ext = (u8 )edid + EDID_LENGTH (i + 1);
		if (edid_ext[0] == CEA_EXT)
		break;
		}

		if (i == edid->extensions)
		return NULL;

		return edid_ext;
		}

		/**
		* drm_detect_hdmi_monitor - detect whether monitor is hdmi.
		* @edid: monitor EDID information
		*
		* Parse the CEA extension according to CEA-861-B.
		* Return true if HDMI, false if not or unknown.
		*/
		bool drm_detect_hdmi_monitor(struct edid *edid)
		{
		u8 *edid_ext;
		int i, hdmi_id;
		int start_offset, end_offset;
		bool is_hdmi = false;

		edid_ext = drm_find_cea_extension(edid);
		if (!edid_ext)
		goto end;

		/* Data block offset in CEA extension block */
		@@ -1324,6 +1341,53 @@ end:
		}
		EXPORT_SYMBOL(drm_detect_hdmi_monitor);

		/**
		* drm_detect_monitor_audio - check monitor audio capability
		*
		* Monitor should have CEA extension block.
		* If monitor has 'basic audio', but no CEA audio blocks, it's 'basic
		* audio' only. If there is any audio extension block and supported
		* audio format, assume at least 'basic audio' support, even if 'basic
		* audio' is not defined in EDID.
		*
		*/
		bool drm_detect_monitor_audio(struct edid *edid)
		{
		u8 *edid_ext;
		int i, j;
		bool has_audio = false;
		int start_offset, end_offset;

		edid_ext = drm_find_cea_extension(edid);
		if (!edid_ext)
		goto end;

		has_audio = ((edid_ext[3] & EDID_BASIC_AUDIO) != 0);

		if (has_audio) {
		DRM_DEBUG_KMS("Monitor has basic audio support\n");
		goto end;
		}

		/* Data block offset in CEA extension block */
		start_offset = 4;
		end_offset = edid_ext[2];

		for (i = start_offset; i < end_offset;
		i += ((edid_ext[i] & 0x1f) + 1)) {
		if ((edid_ext[i] >> 5) == AUDIO_BLOCK) {
		has_audio = true;
		for (j = 1; j < (edid_ext[i] & 0x1f); j += 3)
		DRM_DEBUG_KMS("CEA audio format %d\n",
		(edid_ext[i + j] >> 3) & 0xf);
		goto end;
		}
		}
		end:
		return has_audio;
		}
		EXPORT_SYMBOL(drm_detect_monitor_audio);

		/**
		* drm_add_edid_modes - add modes from EDID data, if available
		* @connector: connector we're probing

include/drm/drm_crtc.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -763,6 +763,7 @@ extern int drm_mode_gamma_get_ioctl(struct drm_device *dev,
		extern int drm_mode_gamma_set_ioctl(struct drm_device *dev,
		void data, struct drm_file file_priv);
		extern bool drm_detect_hdmi_monitor(struct edid *edid);
		extern bool drm_detect_monitor_audio(struct edid *edid);
		extern int drm_mode_page_flip_ioctl(struct drm_device *dev,
		void data, struct drm_file file_priv);
		extern struct drm_display_mode drm_cvt_mode(struct drm_device dev,

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