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

Thu Nov 13 15:57:08 CET 2008

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


-- 
Christian Pellegrin, see http://www.evolware.org/chri/
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