<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - periodic audio skips with Intel HDA" href="https://bugs.freedesktop.org/show_bug.cgi?id=49608#c53">Comment # 53</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - periodic audio skips with Intel HDA" href="https://bugs.freedesktop.org/show_bug.cgi?id=49608">bug 49608</a> from <a class="email" href="mailto:superquad.vortex2@gmail.com" title="Raymond <superquad.vortex2@gmail.com>"> Raymond</a> <pre>as pulseaudio use snd_pcm_rewind() which require the sound card report accurate hwptr position than those sound card which report hwptr position at period bounary when interrupt occur the difference between hda-intel and your ca0106 is the granularity of the pointer callback <a href="https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/include/linux/dmaengine.h">https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/include/linux/dmaengine.h</a> /** * enum dma_residue_granularity - Granularity of the reported transfer residue * @DMA_RESIDUE_GRANULARITY_DESCRIPTOR: Residue reporting is not support. The * DMA channel is only able to tell whether a descriptor has been completed or * not, which means residue reporting is not supported by this channel. The * residue field of the dma_tx_state field will always be 0. * @DMA_RESIDUE_GRANULARITY_SEGMENT: Residue is updated after each successfully * completed segment of the transfer (For cyclic transfers this is after each * period). This is typically implemented by having the hardware generate an * interrupt after each transferred segment and then the drivers updates the * outstanding residue by the size of the segment. Another possibility is if * the hardware supports scatter-gather and the segment descriptor has a field * which gets set after the segment has been completed. The driver then counts * the number of segments without the flag set to compute the residue. * @DMA_RESIDUE_GRANULARITY_BURST: Residue is updated after each transferred * burst. This is typically only supported if the hardware has a progress * register of some sort (E.g. a register with the current read/write address * or a register with the amount of bursts/beats/bytes that have been * transferred or still need to be transferred). */ hda-intel can report DMA_RESIDUE_GRANULARITY_BURST seem both read hwptr from hardware register can your ca0106 report DMA_RESIDUE_GRANULARITY_SEGMENT or DMA_RESIDUE_GRANULARITY_BURST ? <a href="https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/sound/pci/ca0106/ca0106_main.c">https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/sound/pci/ca0106/ca0106_main.c</a> static snd_pcm_uframes_t snd_ca0106_pcm_pointer_playback(struct snd_pcm_substream *substream) { struct snd_ca0106 *emu = snd_pcm_substream_chip(substream); struct snd_pcm_runtime *runtime = substream->runtime; struct snd_ca0106_pcm *epcm = runtime->private_data; unsigned int ptr, prev_ptr; int channel = epcm->channel_id; int timeout = 10; if (!epcm->running) return 0; prev_ptr = -1; do { ptr = snd_ca0106_ptr_read(emu, PLAYBACK_LIST_PTR, channel); ptr = (ptr >> 3) * runtime->period_size; ptr += bytes_to_frames(runtime, snd_ca0106_ptr_read(emu, PLAYBACK_POINTER, channel)); if (ptr >= runtime->buffer_size) ptr -= runtime->buffer_size; if (prev_ptr == ptr) return ptr; prev_ptr = ptr; } while (--timeout); dev_warn(emu->card->dev, "ca0106: unstable DMA pointer!\n"); return 0; } <a href="https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/sound/pci/hda/hda_controller.c">https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/sound/pci/hda/hda_controller.c</a> static snd_pcm_uframes_t azx_pcm_pointer(struct snd_pcm_substream *substream) { struct azx_pcm *apcm = snd_pcm_substream_chip(substream); struct azx *chip = apcm->chip; struct azx_dev *azx_dev = get_azx_dev(substream); return bytes_to_frames(substream->runtime, azx_get_position(chip, azx_dev)); }</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>