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 --- include/sound/hdaudio.h | 3 +++ sound/hda/hdac_controller.c | 12 ++++++++++++ sound/hda/hdac_stream.c | 2 +- 3 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/include/sound/hdaudio.h b/include/sound/hdaudio.h index affedc2..d365297 100644 --- a/include/sound/hdaudio.h +++ b/include/sound/hdaudio.h @@ -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, diff --git a/sound/hda/hdac_controller.c b/sound/hda/hdac_controller.c index bc4a8b6..ac15aa3 100644 --- a/sound/hda/hdac_controller.c +++ b/sound/hda/hdac_controller.c @@ -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); diff --git a/sound/hda/hdac_stream.c b/sound/hda/hdac_stream.c index a314b03..a38a2af 100644 --- a/sound/hda/hdac_stream.c +++ b/sound/hda/hdac_stream.c @@ -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; }