ALSA: hda/tas2781: Add hardware stabilization delay during firmware load retries

During runtime resume transitions, loading calibration data blocks
to the tas2781 amplifier may intermittently trigger transmission
failures or block checksum mismatches (-EAGAIN) due to un-stabilized
power rails or I2C bus glitches.

The loop in tasdev_load_blk() decrements block->nr_retry and attempts
an immediate re-transmission upon receiving -EAGAIN. However, without
any inter-retry delay, all available retry slots are exhausted within
less than a microsecond—long before the hardware can physically
settle. This leads to permanent "ERROR_PRAM_CRCCHK" deadlocks and
silent speakers on modern laptops after resuming media.

Fix this cleanly by introducing a 2ms usleep_range() delay directly
inside the tasdev_load_blk() retry paths prior to each 'continue'
statement. This grants the chip sufficient time to stabilize before
the next transmission attempt without introducing unnecessary latency
on final failures.

Signed-off-by: Zeliang Li <lizeliang.linux@gmail.com>
Link: https://patch.msgid.link/20260815-master-v2-1-b4ea03c8b59e@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Zeliang Li 2026-08-15 03:45:55 +08:00 • committed by Takashi Iwai
commit f6635d64e7