Re: [PATCH] i810_audio fix for version 0.11

[Doug Ledford]

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Doug Ledford wrote:

> Well, unfortunately, neither of the patches you guys sent do what I 
> was looking for ;-)  My goal with that code was to enable a specific 
> certain behaviour, and because of the deadlock I have to make a few 
> changes elsewhere for it to work properly.  The workaround patches are 
> fine for now, but later today I'll make a 0.12 that fixes it the way 
> I'm looking for.  (Hint: it's legal for a program to call SETTRIGGER 
> to disable PCM output, then call the write() routine to fill the 
> buffer, then call SETTRIGGER again to start output, otherwise known as 
> pre buffering, and I want to support that without forcing the DAC to 
> be started on update_lvi())
>
> The real answer is multipart:
>
> 1) during i810_open go back to the old behaviour of setting 
> dmabuf->trigger to PCM_ENABLE_INPUT and/or OUTPUT based on file mode.
>
> 2) make sure that i810_mmap clears dmabuf->trigger
>
> 3) make sure that in both i810_write and i810_read, we force the 
> trigger setting when we can't output/input any data because count <= 0
>
> 4) in update_lvi make the check something like:
>
> if (!dmabuf->enable && dmabuf->trigger) {
>    ....
> }
>
> That should solve the problem, I just haven't written it up yet.
>
>
>
OK, the attached patch should do what is mentioned above.

Doug Ledford

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--- i810_audio.c.11	Thu Dec  6 16:53:41 2001
+++ i810_audio.c.12	Fri Dec  7 13:32:38 2001
@@ -198,7 +198,7 @@
 #define INT_MASK (INT_SEC|INT_PRI|INT_MC|INT_PO|INT_PI|INT_MO|INT_NI|INT_GPI)
 
 
-#define DRIVER_VERSION "0.11"
+#define DRIVER_VERSION "0.12"
 
 /* magic numbers to protect our data structures */
 #define I810_CARD_MAGIC		0x5072696E /* "Prin" */
@@ -952,7 +952,7 @@
 	 * the CIV value to the next sg segment to be played so that when
 	 * we call start_{dac,adc}, things will operate properly
 	 */
-	if (!dmabuf->enable) {
+	if (!dmabuf->enable && dmabuf->trigger) {
 		outb((inb(port+OFF_CIV)+1)&31, port+OFF_LVI);
 		if(rec) {
 			__start_adc(state);
@@ -1111,8 +1111,11 @@
 
 		/* 
 		 * This will make sure that our LVI is correct, that our
-		 * pointer is updated, and that the DAC is running
+		 * pointer is updated, and that the DAC is running.  We
+		 * have to force the setting of dmabuf->trigger to avoid
+		 * any possible deadlocks.
 		 */
+		dmabuf->trigger = PCM_ENABLE_OUTPUT;
 		i810_update_lvi(state,0);
 
 		if (signal_pending(current))
@@ -2280,6 +2283,7 @@
 			card->states[i] = NULL;;
 			return -EBUSY;
 		}
+		dmabuf->trigger |= PCM_ENABLE_INPUT;
 		i810_set_adc_rate(state, 8000);
 	}
 	if(file->f_mode & FMODE_WRITE) {
@@ -2291,6 +2295,7 @@
 		/* Initialize to 8kHz?  What if we don't support 8kHz? */
 		/*  Let's change this to check for S/PDIF stuff */
 	
+		dmabuf->trigger |= PCM_ENABLE_OUTPUT;
 		if ( spdif_locked ) {
 			i810_set_dac_rate(state, spdif_locked);
 			i810_set_spdif_output(state, AC97_EA_SPSA_3_4, spdif_locked);

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