From: Adam Goode <agoode@google.com>
To: patch@alsa-project.org
Cc: Adam Goode <agoode@google.com>,
alsa-devel@alsa-project.org, martin.koegler@chello.at
Subject: [PATCH - alsa-lib 1/1] Change card/pid get functions to return -ENOSYS if the kernel is too old
Date: Fri, 1 Apr 2016 13:33:50 -0400 [thread overview]
Message-ID: <1459532030-6387-1-git-send-email-agoode@google.com> (raw)
When trying to get the pid or card of a client, the get functions will
return -1 if there is no pid or card for a client. Clients have zero or
one of these, so -1 is correct for these cases. But we also need to detect
the case where the kernel cannot tell us if there is a card or pid, so
that userspace can fallback to probing this information in the old way.
Signed-off-by: Adam Goode <agoode@google.com>
diff --git a/src/seq/seq.c b/src/seq/seq.c
index 4405e68..7de1e81 100644
--- a/src/seq/seq.c
+++ b/src/seq/seq.c
@@ -1522,9 +1522,10 @@ int snd_seq_client_info_get_error_bounce(const snd_seq_client_info_t *info)
}
/**
- * \brief Get the sound card number.
+ * \brief Get the sound card number if the kernel supports this.
* \param info client_info container
- * \return card number or -1 if value is not available.
+ * \return card number, -1 if there is no card for this client,
+ * or \c -ENOSYS if the kernel does not have support for this operation
*
* Only available for SND_SEQ_KERNEL_CLIENT clients.
*/
@@ -1535,9 +1536,10 @@ int snd_seq_client_info_get_card(const snd_seq_client_info_t *info)
}
/**
- * \brief Get the owning PID.
+ * \brief Get the owning PID if the kernel supports this.
* \param info client_info container
- * \return pid or -1 if value is not available.
+ * \return pid, -1 if there is no PID for this client,
+ * or \c -ENOSYS if the kernel does not have support for this operation
*
* Only available for SND_SEQ_USER_CLIENT clients.
*/
diff --git a/src/seq/seq_hw.c b/src/seq/seq_hw.c
index 578ef12..a1d1e4a 100644
--- a/src/seq/seq_hw.c
+++ b/src/seq/seq_hw.c
@@ -102,8 +102,8 @@ static int snd_seq_hw_get_client_info(snd_seq_t *seq, snd_seq_client_info_t * in
return -errno;
}
if (hw->version < SNDRV_PROTOCOL_VERSION(1, 0, 2)) {
- info->card = -1;
- info->pid = -1;
+ info->card = -ENOSYS;
+ info->pid = -ENOSYS;
}
return 0;
}
@@ -374,8 +374,8 @@ static int snd_seq_hw_query_next_client(snd_seq_t *seq, snd_seq_client_info_t *i
return -errno;
}
if (hw->version < SNDRV_PROTOCOL_VERSION(1, 0, 2)) {
- info->card = -1;
- info->pid = -1;
+ info->card = -ENOSYS;
+ info->pid = -ENOSYS;
}
return 0;
}
--
2.8.0.rc3.226.g39d4020
next reply other threads:[~2016-04-01 17:34 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-01 17:33 Adam Goode [this message]
2016-04-01 17:45 ` [PATCH - alsa-lib 1/1] Change card/pid get functions to return -ENOSYS if the kernel is too old Adam Goode
2016-04-01 21:15 ` Martin Koegler
2016-04-04 14:54 ` Takashi Iwai
2016-04-05 15:21 ` Adam Goode
2016-04-07 19:23 ` Adam Goode
2016-04-07 20:10 ` Martin Koegler
2016-04-07 23:00 ` Takashi Sakamoto
2016-04-08 10:24 ` Takashi Iwai
2016-04-08 12:56 ` Jaroslav Kysela
2016-04-08 13:10 ` Takashi Iwai
2016-04-08 15:21 ` Adam Goode
2016-04-08 17:56 ` Martin Koegler
2016-04-08 19:53 ` Adam Goode
2016-06-06 13:57 ` Adam Goode
2016-06-06 14:01 ` Takashi Iwai
2017-01-03 13:34 ` Adam Goode
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