On 1/22/19 7:36 PM, Curtis Malainey wrote:
Curtis Malainey | Software Engineer | cujomalainey@xxxxxxxxxx | 650-898-3849
On Wed, Jan 23, 2019 at 4:11 AM Pierre-Louis Bossart
<pierre-louis.bossart@xxxxxxxxxxxxxxx> wrote:
The issue was that we were seeing a memory corruption bug on an AMD
chromebooks with that function already (not observed on Intel). I was
testing some SOF integrations and was seeing this in the kernel logs.
I had Dylan verify my logic before I sent the patch because it took so
long to identify the bug and it was traced to the patch that introduce
soc_init_platform.
[ 10.922112] cz-da7219-max98357a AMD7219:00: ASoC: CPU DAI
designware-i2s.1.auto not registered
[ 10.922122] cz-da7219-max98357a AMD7219:00:
devm_snd_soc_register_card(acpd7219m98357) failed: -517
[ 11.001411] cz-da7219-max98357a AMD7219:00: ASoC: Both platform
name/of_node are set for amd-max98357-play
[ 11.001423] cz-da7219-max98357a AMD7219:00: ASoC: failed to init
link amd-max98357-play
[ 11.001431] cz-da7219-max98357a AMD7219:00:
devm_snd_soc_register_card(acpd7219m98357) failed: -22
[ 11.001577] cz-da7219-max98357a: probe of AMD7219:00 failed with error -22
of_node was never getting set but the pointer was becoming populated
(outside of the probe call) which traced to soc_init_platform function
which was not reallocating memory on a EPROBE_DEFER even though it was
getting freed by devm. I am not very familiar with devm but my local
maintainers say that it should be freeing the memory even on a
PROBE_DEFER.
The patch should mirror the memory behaviour in
snd_soc_init_multicodec which also reallocates its memory on every
probe. I'm not sure how the patch is causing you to defer, is your
component list corrupt?
Sorry for the duplicate spam, forgot to send via plain text mode,
re-sending for the mailing list so it gets accepted.
There is no defer issue with the intel stuff, but we call this routine
multiple times
snd_soc_register_card
--soc_init_dai_link
----snd_soc_init_platform
-- soc_soc_bind_card
----snd_soc_instantiate_card
------ soc_check_tplg_fes
-------- snd_soc_init_platform << ALLOC1
--------soc_init_dai_link
----------snd_soc_init_platform << ALLOC2
Ah that explains it, in my testing I didn't have the patch that
brought in the call from within tplg_fes
Initially dai_link->legacy_platform is 0, so gets set after the first
first devm_kzalloc (ALLOC1) and after that we always allocate new memory
(ALLOC2). The end result is that whatever we set in soc_check_tplg_fes
is lost with the new/unnecessary alloc.
I would guess your solution is also a work-around, if devm_ effectively
freed the memory then the pointer would become NULL. Or may that's the
issue is that no one actually resets it.
Yes, its a work around to fix the memory issue. If you set the
platform in the machine driver the code will ignore it and not reset
it. That being said that is not a full proof workaround and a better
solution is definitely needed. We could go and clean up the pointers
in soc_instantiate_card based on the flag being set. That way we only
relocate on a NULL pointer like we used to but still don't affect
statically allocated memory. I will draft a patch, test it on the AMD
device, reply to this thread later with it, Pierre can you test it as
well?
I am curious why soc_check_tplg_fes is calling snd_soc_init_platform.
It should have already been called earlier, in soc_init_dai_link at
the beginning of snd_soc_register_card so the memory should already be
initialized. Unless I am missing somewhere where links are getting
added between the calls.
This is actually a second order problem, the main issue i have is that
the very first call to init_dai_link fails with the new DEFER_PROBE
handling.
I don't quite understand what Linaro/AMD folks are doing but I trust
their changes are legitimate. To move forward, maybe it's not worth
spending too much time on a grand unification of string theory, there
are simpler solutions: the Intel machine drivers already do get the
platform driver name as an platform_data argument, so we could modify
the dailinks platform names before even registering the card. I tested
with the attached proof-of-concept patch, it adds 2 lines of code per
machine driver if we use a common helper (after the transition to the
"modern" dailink representation that's needed anyways) so maybe it's
better in the end? the override we care about is really the automatic
handling of all the hard-coded front-ends, the platform-name override
isn't really a battle i want to pick or spend time on.
>From 5680c64b09964b134e20bf96142d1ce5dcf0f77f Mon Sep 17 00:00:00 2001
From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Date: Tue, 22 Jan 2019 18:53:43 -0600
Subject: [PATCH] ASoC: add helper to change platform name for all dailinks
To reuse the same machine drivers with Atom/SST, Skylake and SOF, we
need to change the default platform_name (or platforms->name in the
"modern" representation).
So far, this override was done with an automatic override, which was
broken by a set of changes for DT platforms related to deferred probe
handling.
This automatic override is actually not really needed, the machine
driver can already receive the platform name as a platform_data
parameter. This is used e.g. for HDaudio support where we have
different PCI aliases used for different platforms. We can reuse the
same mechanism and modify the machine drivers to override the dailinks
prior to registrating the card.
This will require additional work for SOF, but with this helper it'll
be just two lines of additional code per machine driver which is
reused, not the end of the world.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
include/sound/soc.h | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/include/sound/soc.h b/include/sound/soc.h
index b71b05019c68..59873084f3bd 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -1583,6 +1583,29 @@ struct snd_soc_dai *snd_soc_card_get_codec_dai(struct snd_soc_card *card,
return NULL;
}
+static inline
+int snd_soc_fixup_dai_links_platform_name(struct snd_soc_card *card,
+ const char *platform_name)
+{
+ struct snd_soc_dai_link *dai_link;
+ int i;
+
+ if (!platform_name) /* nothing to do */
+ return 0;
+
+ /* set platform name for each dailink */
+ for_each_card_prelinks(card, i, dai_link) {
+ /* only single platform is supported for now */
+ dai_link->platforms->name = devm_kstrdup(card->dev,
+ platform_name,
+ GFP_KERNEL);
+ if (!dai_link->platforms->name)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
#ifdef CONFIG_DEBUG_FS
extern struct dentry *snd_soc_debugfs_root;
#endif
--
2.17.1
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