Re: [PATCH v3 3/9] ALSA: hda: Introduce snd_hdac_stream_wait_drsm()

On Thu, 27 Oct 2022 10:23:25 +0200, Cezary Rojewski wrote:

--- a/sound/hda/hdac_stream.c +++ b/sound/hda/hdac_stream.c @@ -821,6 +821,27 @@ void snd_hdac_stream_drsm_enable(struct hdac_bus *bus, } EXPORT_SYMBOL_GPL(snd_hdac_stream_drsm_enable);

+/*

• • snd_hdac_stream_wait_drsm - wait for HW to clear RSM for a stream
• • @azx_dev: HD-audio core stream to await RSM for
• • Returns 0 on success and -ETIMEDOUT upon a timeout.
• */

+int snd_hdac_stream_wait_drsm(struct hdac_stream *azx_dev) +{

• struct hdac_bus *bus = azx_dev->bus;
• u32 mask, reg;
• int ret;
• mask = 1 << azx_dev->index;
• ret = readb_poll_timeout(bus->drsmcap + AZX_REG_DRSM_CTL, reg, !(reg & mask), 250, 2000);

Remember that HD-audio bus doesn't always allow readb(). Tegra requires the aligned access, for example.

Takashi