ASoC: topology: disable size checks for bytes_ext controls if needed

When CONFIG_SND_CTL_VALIDATION is set, accesses to extended bytes
control generate spurious error messages when the size exceeds 512
bytes, such as

[ 11.224223] sof_sdw sof_sdw: control 2:0:0:EQIIR5.0 eqiir_coef_5:0:
invalid count 1024

In addition the error check returns -EINVAL which has the nasty side
effect of preventing applications accessing controls from working,
e.g.

root@plb:~# alsamixer
cannot load mixer controls: Invalid argument

It's agreed that the control interface has been abused since 2014, but
forcing a check should not prevent existing solutions from working.

This patch skips the checks conditionally if CONFIG_SND_CTL_VALIDATION
is set and the byte array provided by topology is > 512. This
preserves the checks for all other cases.

Fixes: 1a3232d2f61d2 ('ASoC: topology: Add support for TLV bytes controls')
BugLink: https://github.com/thesofproject/linux/issues/2430
Reported-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Jaska Uimonen <jaska.uimonen@intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20200917103912.2565907-1-kai.vehmanen@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/soc-topology.c b/sound/soc/soc-topology.c
index cee9986..e5ff9a5 100644 (file)
--- a/sound/soc/soc-topology.c
+++ b/sound/soc/soc-topology.c
@@ -592,6 +592,17 @@ static int soc_tplg_kcontrol_bind_io(struct snd_soc_tplg_ctl_hdr *hdr,
                k->info = snd_soc_bytes_info_ext;
                k->tlv.c = snd_soc_bytes_tlv_callback;
 
+               /*
+                * When a topology-based implementation abuses the
+                * control interface and uses bytes_ext controls of
+                * more than 512 bytes, we need to disable the size
+                * checks, otherwise accesses to such controls will
+                * return an -EINVAL error and prevent the card from
+                * being configured.
+                */
+               if (IS_ENABLED(CONFIG_SND_CTL_VALIDATION) && sbe->max > 512)
+                       k->access |= SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK;
+
                ext_ops = tplg->bytes_ext_ops;
                num_ops = tplg->bytes_ext_ops_count;
                for (i = 0; i < num_ops; i++) {