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List:       linux-sound
Subject:    Silly bug in sb_ess.c
From:       Rolf Fokkens <rolf () flits102-126 ! flits ! rug ! nl>
Date:       1999-11-30 22:47:04
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Kernel maintainers,

Cvetan Ivanov pointed out I made a silly programming error in sb_ess.c.  In
2.2 this has been taken care of, it hasn't been taken care of in 2.3. I attached
the patch. 

The bug is probably harmfull for machines that don't have a BIOS which
initializes the chip. In these cases non ES1887 chips will have no
initialization for their DMA channel at all.

I've seen previous problem reports that might be related to this bug as well.

Rolf.




["sb_ess.c-2.3.29.patch" (text/english)]

--- ../new/linux-2.3.29/drivers/sound/sb_ess.c	Sat Oct  2 16:49:30 1999
+++ linux/drivers/sound/sb_ess.c	Wed Oct 27 22:27:01 1999
@@ -10,29 +10,29 @@
  *
  * History:
  *
- * Rolf Fokkens	(Dec 20 1998):	ES188x recording level support on a per
+ * Rolf Fokkens	 (Dec 20 1998):	ES188x recording level support on a per
  * fokkensr@vertis.nl			input basis.
- *				(Dec 24 1998):	Recognition of ES1788, ES1887, ES1888,
+ *				 (Dec 24 1998):	Recognition of ES1788, ES1887, ES1888,
  *								ES1868, ES1869 and ES1878. Could be used for
  *								specific handling in the future. All except
  *								ES1887 and ES1888 and ES688 are handled like
  *								ES1688.
- *				(Dec 27 1998):	RECLEV for all (?) ES1688+ chips. ES188x now
+ *				 (Dec 27 1998):	RECLEV for all (?) ES1688+ chips. ES188x now
  *								have the "Dec 20" support + RECLEV
- *				(Jan  2 1999):	Preparation for Full Duplex. This means
+ *				 (Jan  2 1999):	Preparation for Full Duplex. This means
  *								Audio 2 is now used for playback when dma16
  *								is specified. The next step would be to use
  *								Audio 1 and Audio 2 at the same time.
- *				(Jan  9 1999):	Put all ESS stuff into sb_ess.[ch], this
+ *				 (Jan  9 1999):	Put all ESS stuff into sb_ess.[ch], this
  *								includes both the ESS stuff that has been in
  *								sb_*[ch] before I touched it and the ESS support
  *								I added later
- *				(Jan 23 1999):	Full Duplex seems to work. I wrote a small
+ *				 (Jan 23 1999):	Full Duplex seems to work. I wrote a small
  *								test proggy which works OK. Haven't found
  *								any applications to test it though. So why did
  *								I bother to create it anyway?? :) Just for
  *								fun.
- *				(May  2 1999):	I tried to be too smart by "introducing"
+ *				 (May  2 1999):	I tried to be too smart by "introducing"
  *								ess_calc_best_speed (). The idea was that two
  *								dividers could be used to setup a samplerate,
  *								ess_calc_best_speed () would choose the best.
@@ -40,10 +40,12 @@
  *								recording problems for high samplerates. I
  *								fixed this by removing ess_calc_best_speed ()
  *								and just doing what the documentation says. 
- * Andy Sloane  (June 4 1999):  Stole some code from ALSA to fix the playback
+ * Andy Sloane   (Jun  4 1999): Stole some code from ALSA to fix the playback
  * andy@guildsoftware.com		speed on ES1869, ES1879, ES1887, and ES1888.
  * 								1879's were previously ignored by this driver;
  * 								added (untested) support for those.
+ * Cvetan Ivanov (Oct 27 1999): Fixed ess_dsp_init to call ess_set_dma_hw for
+ * zezo@inet.bg					_ALL_ ESS models, not only ES1887
  *
  * This files contains ESS chip specifics. It's based on the existing ESS
  * handling as it resided in sb_common.c, sb_mixer.c and sb_audio.c. This
@@ -52,7 +54,7 @@
  * - RECLEV support for ES1688 and later
  * - 6 bits playback level support chips later than ES1688
  * - Recording level support on a per-device basis for ES1887
- * - Full-Duplex for ES1887 (under development)
+ * - Full-Duplex for ES1887
  *
  * Full duplex is enabled by specifying dma16. While the normal dma must
  * be one of 0, 1 or 3, dma16 can be one of 0, 1, 3 or 5. DMA 5 is a 16 bit
@@ -100,7 +102,7 @@
  * of writing 0x00 to 0x7f (which should be done by reset): The ES1887 moves
  * into ES1888 mode. This means that it claims IRQ 11, which happens to be my
  * ISDN adapter. Needless to say it no longer worked. I now understand why
- * after rebooting 0x7f already was 0x05, the value of my choise: the BIOS
+ * after rebooting 0x7f already was 0x05, the value of my choice: the BIOS
  * did it.
  *
  * Oh, and this is another trap: in ES1887 docs mixer register 0x70 is decribed
@@ -1200,10 +1202,10 @@
 
 	/* AAS: info stolen from ALSA: these boards have different clocks */
 	switch(devc->submodel) {
-/* APPARENTLY NOT 1869 
+/* APPARENTLY NOT 1869 AND 1887
 		case SUBMDL_ES1869:
-*/		
 		case SUBMDL_ES1887:
+*/		
 		case SUBMDL_ES1888:
 			devc->caps |= SB_CAP_ES18XX_RATE;
 			break;
@@ -1305,6 +1307,13 @@
 int ess_dsp_init (sb_devc *devc, struct address_info *hw_config)
 {
 	/*
+	 * Caller also checks this, but anyway
+	 */
+	if (devc->model != MDL_ESS) {
+		printk (KERN_INFO "ess_dsp_init for non ESS chip\n");
+		return 1;
+	}
+	/*
 	 * This for ES1887 to run Full Duplex. Actually ES1888
 	 * is allowed to do so too. I have no idea yet if this
 	 * will work for ES1888 however.
@@ -1324,15 +1333,12 @@
 		if (devc->dma8 != devc->dma16 && devc->dma16 != -1) {
 			devc->duplex = 1;
 		}
-
-		if (!ess_set_dma_hw (devc)) {
-			free_irq(devc->irq, devc);
-			return 0;
-		}
-		return 1;
-	} else {
-		return -1;
 	}
+	if (!ess_set_dma_hw (devc)) {
+		free_irq(devc->irq, devc);
+		return 0;
+	}
+	return 1;
 }
 
 /****************************************************************************


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