git: 602ea0ced129 - stable/14 - sound: Fix OSS API requests for more than 8 channels

The branch stable/14 has been updated by emaste:

URL: https://cgit.FreeBSD.org/src/commit/?id=602ea0ced129b89c972b6ce6fe5242d0a379c33b

commit 602ea0ced129b89c972b6ce6fe5242d0a379c33b
Author:     Florian Walpen <dev@submerge.ch>
AuthorDate: 2023-11-25 00:04:34 +0000
Commit:     Ed Maste <emaste@FreeBSD.org>
CommitDate: 2024-03-25 22:28:30 +0000

    sound: Fix OSS API requests for more than 8 channels
    
    Audio devices with more than 8 channels need bitperfect mode to operate,
    the vchan processing chain is limited to 8 channels. For these devices,
    let applications properly select a certain number of channels supported
    by the driver, instead of mapping the request to a vchan format.
    
    Reviewed by:    emaste
    Pull Request:   https://github.com/freebsd/freebsd-src/pull/914
    
    (cherry picked from commit 61c831679615d2a03a494bd7f3627fb945f2795c)
---
 sys/dev/sound/pcm/dsp.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/sys/dev/sound/pcm/dsp.c b/sys/dev/sound/pcm/dsp.c
index 5aa7979b98c9..9040c77893d4 100644
--- a/sys/dev/sound/pcm/dsp.c
+++ b/sys/dev/sound/pcm/dsp.c
@@ -1502,24 +1502,31 @@ dsp_ioctl(struct cdev *i_dev, u_long cmd, caddr_t arg, int mode,
 
     	case SOUND_PCM_WRITE_CHANNELS:
 /*	case SNDCTL_DSP_CHANNELS: ( == SOUND_PCM_WRITE_CHANNELS) */
-		if (*arg_i < 0) {
+		if (*arg_i < 0 || *arg_i > AFMT_CHANNEL_MAX) {
 			*arg_i = 0;
 			ret = EINVAL;
 			break;
 		}
 		if (*arg_i != 0) {
-			struct pcmchan_matrix *m;
-			uint32_t ext;
+			uint32_t ext = 0;
 
 			tmp = 0;
-			if (*arg_i > SND_CHN_MAX)
-				*arg_i = SND_CHN_MAX;
+			/*
+			 * Map channel number to surround sound formats.
+			 * Devices that need bitperfect mode to operate
+			 * (e.g. more than SND_CHN_MAX channels) are not
+			 * subject to any mapping.
+			 */
+			if (!(dsp_get_flags(i_dev) & SD_F_BITPERFECT)) {
+				struct pcmchan_matrix *m;
 
-			m = feeder_matrix_default_channel_map(*arg_i);
-			if (m != NULL)
-				ext = m->ext;
-			else
-				ext = 0;
+				if (*arg_i > SND_CHN_MAX)
+					*arg_i = SND_CHN_MAX;
+
+				m = feeder_matrix_default_channel_map(*arg_i);
+				if (m != NULL)
+					ext = m->ext;
+			}
 
 			PCM_ACQUIRE_QUICK(d);
 	  		if (wrch) {