ALSA: hda: add member to store ratio for stripe control (67ae482a) · Commits · 戴 / test

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:

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

Takashi Iwai <tiwai@suse.de>

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;
		}

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