static bool pcm_status_mmap_allowed(struct snd_pcm_file *pcm_file)
{
+ /* If drivers require the explicit sync (typically for non-coherent
+ * pages), we have to disable the mmap of status and control data
+ * to enforce the control via SYNC_PTR ioctl.
+ */
+ if (pcm_file->substream->runtime->hw.info & SNDRV_PCM_INFO_EXPLICIT_SYNC)
+ return false;
/* See pcm_control_mmap_allowed() below.
* Since older alsa-lib requires both status and control mmaps to be
* coupled, we have to disable the status mmap for old alsa-lib, too.
{
if (pcm_file->no_compat_mmap)
return false;
+ /* see above */
+ if (pcm_file->substream->runtime->hw.info & SNDRV_PCM_INFO_EXPLICIT_SYNC)
+ return false;
/* Disallow the control mmap when SYNC_APPLPTR flag is set;
* it enforces the user-space to fall back to snd_pcm_sync_ptr(),
* thus it effectively assures the manual update of appl_ptr.