ALSA: rawmidi: introduce SNDRV_RAWMIDI_IOCTL_USER_PVERSION

The new framing mode causes the user space regression, because
the alsa-lib code does not initialize the reserved space in
the params structure when the device is opened.

This change adds SNDRV_RAWMIDI_IOCTL_USER_PVERSION like we
do for the PCM interface for the protocol acknowledgment.

Cc: David Henningsson <coding@diwic.se>
Cc: <stable@vger.kernel.org>
Fixes: 08fdced60ca0 ("ALSA: rawmidi: Add framing mode")
BugLink: https://github.com/alsa-project/alsa-lib/issues/178
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20210920171850.154186-1-perex@perex.cz
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/include/sound/rawmidi.h b/include/sound/rawmidi.h
index 989e151..7a08ed2 100644 (file)
--- a/include/sound/rawmidi.h
+++ b/include/sound/rawmidi.h
@@ -98,6 +98,7 @@ struct snd_rawmidi_file {
        struct snd_rawmidi *rmidi;
        struct snd_rawmidi_substream *input;
        struct snd_rawmidi_substream *output;
+       unsigned int user_pversion;     /* supported protocol version */
 };
 
 struct snd_rawmidi_str {

diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
index 1d84ec9..5859ca0 100644 (file)
--- a/include/uapi/sound/asound.h
+++ b/include/uapi/sound/asound.h
@@ -784,6 +784,7 @@ struct snd_rawmidi_status {
 
 #define SNDRV_RAWMIDI_IOCTL_PVERSION   _IOR('W', 0x00, int)
 #define SNDRV_RAWMIDI_IOCTL_INFO       _IOR('W', 0x01, struct snd_rawmidi_info)
+#define SNDRV_RAWMIDI_IOCTL_USER_PVERSION _IOW('W', 0x02, int)
 #define SNDRV_RAWMIDI_IOCTL_PARAMS     _IOWR('W', 0x10, struct snd_rawmidi_params)
 #define SNDRV_RAWMIDI_IOCTL_STATUS     _IOWR('W', 0x20, struct snd_rawmidi_status)
 #define SNDRV_RAWMIDI_IOCTL_DROP       _IOW('W', 0x30, int)

diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 6c0a4a6..6f30231 100644 (file)
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -873,12 +873,21 @@ static long snd_rawmidi_ioctl(struct file *file, unsigned int cmd, unsigned long
                        return -EINVAL;
                }
        }
+       case SNDRV_RAWMIDI_IOCTL_USER_PVERSION:
+               if (get_user(rfile->user_pversion, (unsigned int __user *)arg))
+                       return -EFAULT;
+               return 0;
+
        case SNDRV_RAWMIDI_IOCTL_PARAMS:
        {
                struct snd_rawmidi_params params;
 
                if (copy_from_user(&params, argp, sizeof(struct snd_rawmidi_params)))
                        return -EFAULT;
+               if (rfile->user_pversion < SNDRV_PROTOCOL_VERSION(2, 0, 2)) {
+                       params.mode = 0;
+                       memset(params.reserved, 0, sizeof(params.reserved));
+               }
                switch (params.stream) {
                case SNDRV_RAWMIDI_STREAM_OUTPUT:
                        if (rfile->output == NULL)