"noise" while recording with an OPL3SAx

Hi,

I have a Toshiba Satellite 2540CDT with an OPL3SAx soundcard and I noticed that there is noise in the sample when I record even when there is nothing connected to the inputs (mic/line/..).
I tried Alsa and I noticed that with Alsa there is no more noise but If I boot again with OSS the noise is back when recording. I also noticed that the noise disappear when using OSS after unloading Alsa modules. So I've made a patch for OSS (by looking at Alsa driver source) that fix this noise but before posting the patch I'd like to know if someone else noticed this noise with OSS or if it occurs only with me ?

Thanks

P.S. I'm using RH6.2 kernel 2.2.14-5.0 and 2.4.0-test4

Hi Jérôme!

I use the Toshiba Satellite 300CDS with a OPL3SAx and I have the same noice. If I want to record something over my mic I have it but I have it also when I use the inline. So please send me the patch.

I use RH6.1beta kernel 2.2.16

Cu
Rainer

Computer programmers do it byte by byte.

I'm unfamiliar with both your Satellite and your Red Hat, so perhaps I should keep my mouth shut. But the combination you describe makes me think of how Alsa mutes the mike (and everything else) and OSS (I think) doesn't, so if your machine has a built-in mike, you may be mixing in computer and other background noises without realizing it, until you run Alsa and it mutes the mike. If I'm write, setting a mute mike with aumix, say, doing a save there, and then running aumix -L when you log in, might solve the problem.

Regards,
- Irving
-

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Hi I.S.Wolfe!

Yes, the problem is also there. I have an external mic and even when I plug it out and record something from my MD I have the same noises. So it would not be the mic. At the first time I thought it was the mic but this is not so.

Cu
Rainer

All programmers are optimists.  Perhaps this modern sorcery especially attracts
those who believe in happy endings and fairy godmothers.  Perhaps the hundreds
of nitty frustrations drive away all but those who habitually focus on the end
goal.  Perhaps it is merely that computers are young, programmers are younger,
and the young are always optimists.  But however the selection process works,
the result is indisputable:  "This time it will surely run," or "I just found
the last bug."
		-- Frederick Brooks, "The Mythical Man Month"

I thought it was a problem with some input level/gain but when sampling my voice, for example, and then later listening at it I could hear my voice + some "scratch" noises.
This is a quick patch based on comparison between OSS and Alsa driver initialization. I'm not an expert with kernel/sound programming so test this patch and tell me if I'm wrong somewhere ...

I tested it with kernel 2.2.14 and 2.4.0-test4.

diff -u --recursive linux-2.4.0-test4.orig/drivers/sound/opl3sa2.c linux-2.4.0-test4/drivers/sound/opl3sa2.c
@@ -598,6 +598,15 @@
    	request_region(hw_config->io_base, 2, chipset_name);
 
 	devc->cfg_port = hw_config->io_base;
+
+	/*printk("OPL3-SAx dma init  ...");*/
+	if( hw_config->dma == hw_config->dma2 ) {
+		/*printk(" DMA1=DMA2=%d\n", hw_config->dma );*/
+		opl3sa2_write(devc->cfg_port, 0x06, 0x03);
+	} else {
+		/*printk(" DMA1=%d DMA2=%d\n", hw_config->dma, hw_config->dma2);*/
+		opl3sa2_write(devc->cfg_port, 0x06, 0x21);
+	}
 }
 
 

Moin Jérôme!

Jérôme Augé schrieb am Sonntag, den 16. Juli 2000:

with 2.2.16 it works great.

Thanks

Cu
Rainer

What the hell is it good for?
		-- Robert Lloyd (engineer of the Advanced Computing Systems
		   Division of IBM), to colleagues who insisted that the
		   microprocessor was the wave of the future, c. 1968

On Sun, 16 Jul 2000, Jirtme Augi wrote:

[snip]

I'm currently at OLS, but I'll look at the patch in more detail when I get home. When I pieced together the OSS OPL3-SAx driver that's in the kernel I assumed that the recording limitations were in the under- lying ad1848 code, but obviously I missed something in Yamaha's docs. I'm planning on sending a patch for 2.4.0-test to Linus/Alan soon after OLS, as a couple of people have sent me PnP integration code that I need to merge and test.

Scott

======================================Scott Murray                                        email: [email protected]
http://www.interlog.com/~scottm                       ICQ: 10602428
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