Commit 67ae482a authored by Sameer Pujar's avatar Sameer Pujar Committed by Takashi Iwai
Browse files

ALSA: hda: add member to store ratio for stripe control 



Stripe control programming is governed by following formula, which is
referenced from the HD Audio specification(Revision 1.0a).
  { ((num_channels * bits_per_sample) / number of SDOs) >= 8 }

Currently above is implemented in snd_hdac_get_stream_stripe_ctl().
This patch introduces a structure member to store the default factor
of '8'. If any HW wants to use a different value, this member can be
easily updated.

Signed-off-by: default avatarSameer Pujar <spujar@nvidia.com>
Link: https://lore.kernel.org/r/1588580176-2801-3-git-send-email-spujar@nvidia.com


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent bb9b02a4

include/sound/hdaudio.h

+3 −0
Original line number Diff line number Diff line
@@ -364,6 +364,9 @@ struct hdac_bus { 
	/* link management */

	struct list_head hlink_list;

	bool cmd_dma_state;



	/* factor used to derive STRIPE control value */

	unsigned int sdo_limit;

};



int snd_hdac_bus_init(struct hdac_bus *bus, struct device *dev,

sound/hda/hdac_controller.c

+12 −0
Original line number Diff line number Diff line
@@ -527,6 +527,18 @@ bool snd_hdac_bus_init_chip(struct hdac_bus *bus, bool full_reset) 
	}



	bus->chip_init = true;



	/*

	 * Default value of '8' is as per the HD audio specification (Rev 1.0a).

	 * Following relation is used to derive STRIPE control value.

	 *  For sample rate <= 48K:

	 *   { ((num_channels * bits_per_sample) / number of SDOs) >= 8 }

	 *  For sample rate > 48K:

	 *   { ((num_channels * bits_per_sample * rate/48000) /

	 *	number of SDOs) >= 8 }

	 */

	bus->sdo_limit = 8;



	return true;

}

EXPORT_SYMBOL_GPL(snd_hdac_bus_init_chip);

sound/hda/hdac_stream.c

+1 −1
Original line number Diff line number Diff line
@@ -38,7 +38,7 @@ int snd_hdac_get_stream_stripe_ctl(struct hdac_bus *bus, 
		else

			value = (channels * bits_per_sample) / sdo_line;



		if (value >= 8)

		if (value >= bus->sdo_limit)

			break;

	}