[alsa-devel] possible problem in s3c24xx-pcm.c in git-devel branch

Hi,

during the porting the uda134x driver to the git devel branch of ALSA SOC I noticed a possible problem in s3c24xx-pcm.c. s3c24xx_pcm_enqueue gained a new parameter that specifies the maximum number of periods that can be enqueued. In s3c24xx_pcm_prepare, which is called on play/capture start, this is limited to 1. Unfortunately on the 2410 the result of this change is that the DMA is stopped because the autoload of the next DMA descriptor doesn't work. I copied a log at the end of this email. Look for DMT==00 after the irq signaling the end of the first period and the subsequent fail of DMA loading since the channel is stopped.

Now I fixed with:

--- a/sound/soc/s3c24xx/s3c24xx-pcm.c +++ b/sound/soc/s3c24xx/s3c24xx-pcm.c @@ -253,7 +253,7 @@ static int s3c24xx_pcm_prepare(struct snd_pcm_substream *substream) prtd->dma_pos = prtd->dma_start;

/* enqueue dma buffers */ - s3c24xx_pcm_enqueue(substream, 1); + s3c24xx_pcm_enqueue(substream, 2);

return ret; }

but this really could be "playing with DMA" since I'm not sure why there is a 1 (since min_period is 2 I would guess 2 is the right value). Anyway with this change play and capture work well.

# /opt/arm/alsa/bin/aplay /mp3z/prova.wav s3c24xx-pcm: Entered s3c24xx_pcm_open s3c24xx_uda134x_startup 0 31250, 132031, 66015, 44010, 33007, 26406, 22005, 18861, 16503, 14670, 13203, 12002, 11002, 10156, 9430, 8802, 8251, 7766, 7335, 6949, 6601, 6287, 6001, 5740, 5501, 5281, 5078, 4890, 4715, 4552, 4401, 4259, 4125, 46875, 198046, 99023, 66015, 49511, 39609, 33007, 28292, 24755, 22005, 19804, 18004, 16503, 15234, 14146, 13203, 12377, 11649, 11002, 10423, 9902, 9430, 9002, 8610, 8251, 7921, 7617, 7335, 7073, 6829, 6601, 6388, 6188, Playing WAVE '/mp3z/prova.wav' : Signed 16 bit Little Endian, Rate 8000 Hz, Mono s3c24xx_uda134x_hw_params desired rate 8000, 58 s3c24xx_uda134x_hw_params will use: 256FS PCLK 24 sysclk 2048000 err 79 uda134x_set_dai_fmt fmt: 00003000 s3c24xx-i2s: Entered s3c24xx_i2s_set_fmt s3c24xx-i2s: hw_params r: IISMOD: 9 s3c24xx-i2s: hw_params w: IISMOD: 9 s3c24xx-i2s: Entered s3c24xx_i2s_set_sysclk s3c24xx-i2s: Entered s3c24xx_i2s_set_clkdiv s3c24xx-i2s: Entered s3c24xx_i2s_set_clkdiv s3c24xx-i2s: Entered s3c24xx_i2s_set_clkdiv uda134x_set_dai_sysclk clk_id: 0, freq: 2048000, dir: 1 uda134x_hw_params sysclk: 2048000, rate:8000 uda134x_hw_params dai_fmt: 12288, params_format:2 uda134x_write reg: 08, value:20 s3c24xx-i2s: Entered s3c24xx_i2s_hw_params s3c24xx-i2s: hw_params r: IISMOD: 9 s3c24xx-i2s: hw_params w: IISMOD: 9 s3c24xx-pcm: Entered s3c24xx_pcm_hw_params s3c24xx-pcm: params bf0673f4, client bf067404, channel 10 dma10: s3c2410_request_dma: client=I2S PCM Stereo out, dev=00000000 mapped channel 10 to 2 dma2: s3c2410_dma_request:755: ls=0, cur=c326b020, 00000000 c326b020 dma2: s3c2410_dma_request:755: DCSRC=332a05c4, DISRC=332a0000, DSTAT=00000000 DMT=04, DCON=a0d00000 dma10: s3c2410_dma_request : requesting irq 35 s3c2410_dma_request: channel initialised, c044fdd4 s3c2410_dma_set_buffdone_fn: chan=c044fdd4, callback rtn=bf05d108 s3c24xx-pcm: Entered s3c24xx_pcm_mmap s3c24xx-pcm: Entered s3c24xx_pcm_prepare s3c2410_dma_devconfig: source=1, hwcfg=00000003, devaddr=55000010 s3c2410_dma_devconfig: mem source, devaddr=55000010, hwcfg=3 s3c2410_dma_config: chan=10, xfer_unit=2, dcon=80000000 s3c2410_dma_config: Initial dcon is 80000000 s3c2410_dma_config: New dcon is 80000000 s3c2410_dma_config: dcon now a0900000 s3c2410_dma_flush: chan c044fdd4 (2) dma2: s3c2410_dma_flush:912: ls=0, cur=c326b020, 00000000 c326b020 dma2: s3c2410_dma_flush:912: DCSRC=332a05c4, DISRC=332a0000, DSTAT=00000000 DMT=04, DCON=a0d00000 s3c2410_dma_flush: free buffer c326b020, next 00000000 s3c24xx-pcm: Entered s3c24xx_audio_buffdone dma2: s3c2410_dma_flush:939: DCSRC=332a05c4, DISRC=332a0000, DSTAT=00000000 DMT=04, DCON=a0d00000 dma2: s3c2410_dma_flush:954: DCSRC=332a05c4, DISRC=332a0000, DSTAT=00000000 DMT=04, DCON=a0d00000 s3c24xx-pcm: Entered s3c24xx_pcm_enqueue dma_max 1 s3c24xx-pcm: dma_loaded: 0 pos: 332a0000 len: 4096 dma_max: 1 dma_end: 332a3e80 s3c2410_dma_enqueue: id=c31fa300, data=332a0000, size=4096 s3c2410_dma_enqueue: buffer c326b020 queued onto empty channel s3c24xx-pcm: ret 0 period 4096 uda134x_mute mute: 0 uda134x_write reg: 0C, value:80 s3c24xx-pcm: Entered s3c24xx_pcm_trigger s3c2410_start_dma: channel=2 s3c2410_chan_loadbuffer: loading buff c326b020 (0x332a0000,0x001000) load_state is none, checking for noreload (next=00000000) dma2: s3c2410_dma_start:366: ls=1, cur=c326b020, 00000000 c326b020 dma2: s3c2410_dma_start:366: DCSRC=332a05c4, DISRC=332a0000, DSTAT=00000000 DMT=04, DCON=a0d00800 dma2: 00000002 to DMASKTRIG dma2: s3c2410_dma_start:394: ls=1, cur=c326b020, 00000000 c326b020 dma2: s3c2410_dma_start:394: DCSRC=332a05c4, DISRC=332a0000, DSTAT=00000000 DMT=02, DCON=a0d00800 dma2: s3c2410_dma_started:967: ls=1, cur=c326b020, 00000000 c326b020 dma2: s3c2410_dma_started:967: DCSRC=332a05c4, DISRC=332a0000, DSTAT=00000000 DMT=02, DCON=a0d00800 s3c24xx-i2s: Entered s3c24xx_i2s_trigger s3c24xx-i2s: Entered s3c24xx_snd_is_clkmaster s3c24xx-i2s: Entered s3c24xx_snd_txctrl s3c24xx-i2s: r: IISCON: 10f IISMOD: 9 IISFCON: 0 s3c24xx-i2s: w: IISCON: 127 IISMOD: 89 IISFCON: a000 s3c24xx-pcm: Entered s3c24xx_pcm_pointer s3c24xx-pcm: Pointer 332a0158 55000010 dma2: s3c2410_dma_irq:608: ls=1, cur=c326b020, 00000000 c326b020 dma2: s3c2410_dma_irq:608: DCSRC=332a1000, DISRC=332a0000, DSTAT=00000000 DMT=00, DCON=a0d00800 s3c24xx-pcm: Entered s3c24xx_audio_buffdone s3c24xx-pcm: Entered s3c24xx_pcm_pointer s3c24xx-pcm: Pointer 332a1000 55000010 s3c24xx-pcm: Entered s3c24xx_pcm_enqueue dma_max 0 s3c24xx-pcm: dma_loaded: 0 pos: 332a1000 len: 4096 dma_max: 2 dma_end: 332a3e80 s3c2410_dma_enqueue: id=c31fa300, data=332a1000, size=4096 s3c2410_dma_enqueue: buffer c326b040 queued onto empty channel s3c2410_chan_loadbuffer: loading buff c326b040 (0x332a1000,0x001000) load_state is none, checking for noreload (next=00000000) s3c24xx-pcm: ret 0 period 4096 s3c24xx-pcm: dma_loaded: 1 pos: 332a2000 len: 4096 dma_max: 2 dma_end: 332a3e80 s3c2410_dma_enqueue: id=c31fa300, data=332a2000, size=4096 dma2: s3c2410_dma_enqueue: buffer c326b000 queued onto non-empty channel dma2: loadbuffer:timeout loading buffer dma2: s3c2410_dma_enqueue:517: ls=1, cur=c326b040, c326b000 c326b000 dma2: s3c2410_dma_enqueue:517: DCSRC=332a1000, DISRC=332a1000, DSTAT=00000000 DMT=00, DCON=a0d00800 s3c24xx-pcm: ret -22 period 4096 dma2: timeout waiting for load (s3c2410_dma_irq) s3c24xx-pcm: Entered s3c24xx_pcm_pointer s3c24xx-pcm: Pointer 332a1000 55000010 s3c24xx-pcm: Entered s3c24xx_pcm_pointer s3c24xx-pcm: Pointer 332a1000 55000010 ^CAborted by signals3c24xx-pcm: Entered s3c24xx_pcm_trigger s3c2410_dma_dostop: dma2: s3c2410_dma_dostop:857: ls=1, cur=c326b040, c326b000 c326b000 dma2: s3c2410_dma_dostop:857: DCSRC=332a1000, DISRC=332a1000, DSTAT=00000000 DMT=00, DCON=a0d00800 s3c24xx-i2s: Entered s3c24xx_i2s_trigger s3c24xx-i2s: Entered s3c24xx_snd_txctrl s3c24xx-i2s: r: IISCON: 127 IISMOD: 89 IISFCON: a000