Re: [PATCH v2 2/4] ALSA: hda: Rework snd_hdac_stream_reset() to use macros

From: Jon Hunter
Date: Wed Oct 05 2022 - 10:26:37 EST

On 05/10/2022 15:07, Takashi Iwai wrote:
On Wed, 05 Oct 2022 15:52:01 +0200,
Jon Hunter wrote:

On 05/10/2022 13:29, Takashi Iwai wrote:


HDA playback is failing on -next for various Tegra boards. Bisect is
point to this commit and reverting it fixes the problem. I was a bit
puzzled why this change is causing a problem, but looking closer there
is a difference between the previous code that was calling
snd_hdac_stream_readb() and the new code that is calling
snd_hdac_stream_readb_poll(). The function snd_hdac_stream_readb()
calls snd_hdac_aligned_mmio() is see if the device has an aligned MMIO
which Tegra does and then would call snd_hdac_aligned_read(). However,
now the code always call readb() and this is breaking Tegra.

So it is either necessary to update snd_hdac_stream_readb_poll() to
handle this or revert this change.

Does the patch below work?



-- 8< --
--- a/include/sound/hdaudio.h
+++ b/include/sound/hdaudio.h
@@ -592,8 +592,8 @@ int snd_hdac_get_stream_stripe_ctl(struct hdac_bus *bus,
#define snd_hdac_stream_readb(dev, reg) \
snd_hdac_reg_readb((dev)->bus, (dev)->sd_addr + AZX_REG_ ## reg)
#define snd_hdac_stream_readb_poll(dev, reg, val, cond, delay_us, timeout_us) \
- readb_poll_timeout((dev)->sd_addr + AZX_REG_ ## reg, val, cond, \
- delay_us, timeout_us)
+ read_poll_timeout(snd_hdac_reg_readb, val, cond, delay_us, timeout_us,\
+ false, (dev)->bus, (dev)->sd_addr + AZX_REG_ ## reg)
#define snd_hdac_stream_readl_poll(dev, reg, val, cond, delay_us, timeout_us) \
readl_poll_timeout((dev)->sd_addr + AZX_REG_ ## reg, val, cond, \
delay_us, timeout_us)

Amazingly it does not work. I would have thought that would, but it
does not. I am a bit puzzled by that?

Interesting, it must be a subtle difference.
What about passing true? It seems that the original code has the
udelay(3) before the loop.

I wondered the same and tried that, but still not working.