Takashi Iwai wrote:
Martin Koegler wrote:
rawmidi devices expose the card number via IOCTLs, which allows to find the corresponding device in sysfs.
The sequencer provides no identifing data. Chromium works around this issue by scanning rawmidi as well as sequencer devices and matching them by using assumtions, how the kernel register sequencer devices.
This changes adds support for exposing the card number for kernel clients as well as the PID for user client.
The minor of the API version is changed to distinguish between the zero initialised reserved field and card number 0.
Signed-off-by: Martin Koegler martin.koegler@chello.at
+++ b/include/uapi/sound/asequencer.h @@ -357,7 +357,8 @@ struct snd_seq_client_info {
- char reserved[64]; /* for future use */
- int owner; /* RO: card number[kernel] / PID[user] */
- char reserved[64 - sizeof(int)]; /* for future use */
The sizeof(int) is always 4. So let's make it explicit.
But, please make sure that this change won't lead to any incompatibility. Some architectures might align with 64bit long, although the 32bit int and the rest char[] should be fine on all known architectures, AFAIK.
Or just make it two fields, card and pid. The two values are currently exclusive, but there is no technical reason for this.
Regards, Clemens