Hi,
first of all, I don't know C and I am no expert, so please apologize if
some of
my questions/comments are stupid.
I have a yamaha based sound card which works with the opl3sa2 driver.
However,
the isapnp activation of this card fails (this has been broken ever
since the 2.4 series).
So I did some investigations and eventually found out that the reason is
the following
check from isapnp_check_dma(..) in isapnp.c:
-------------
/* Some machines allow DMA 0, but others don't. In fact on some
boxes DMA 0 is the memory refresh. Play safe */
if (dma < 1 || dma == 4 || dma > 7)
return 1;
--------------
However, the opl3sa2 card insists on dma=0,dma2=1. In particular, if I
change
"(dma < 1 || dma == 4 || dma > 7)" to "(dma < 0 || dma == 4 || dma > 7)"
everything
works fine.
Now I am wondering what should be done:
1) Make the above change to isapnp.c. According to the above comment
this will break
some other boxes, so probably this should be configurable via /proc/isapnp.
2) Change opl3sa2.c and force isapnp to use dma=0 (a patch can be found
at the end of this
message).
What do the experts think is the right way to fix this problem?
A few further remarks concerning my patch:
*) The patch also adds a line "opl3sa2_state[card].activated = 1" which
is an
obvious omission in the original driver.
*) I have to force the driver to use both dma=0 and dma2=1. From what I
understand dma=0 should be sufficient, but this will not work. Looks like
a bug in isapnp.c to me. However, this should do no harm since according
to /proc/isapnp, the card only offers these values anyway.
Thanks for your comments,
Gerald
-----------------------------------------------
--- drivers/sound/opl3sa2.c.orig Thu May 2 23:36:45 2002
+++ drivers/sound/opl3sa2.c Sun Jun 2 15:19:44 2002
@@ -57,6 +57,7 @@
* (Jan 7, 2001)
* Zwane Mwaikambo Added PM support. (Dec 4 2001)
* Zwane Mwaikambo Code, data structure cleanups. (Feb 15 2002)
+ * Gerald Teschl Fixed ISA PnP activate. (Jun 02 2002)
*
*/
@@ -868,8 +869,15 @@
opl3sa2_state[card].activated = 1;
}
else {
+ /* isapnp.c disallows dma=0 but the opl3sa2 card only
accepts this value */
+ if (!dev->ro) {
+ isapnp_resource_change(&dev->dma_resource[0], 0, 1);
+ isapnp_resource_change(&dev->dma_resource[1], 1, 1);
+ }
+ opl3sa2_state[card].activated = 1;
+
if(dev->activate(dev) < 0) {
- printk(KERN_WARNING PFX "ISA PnP activate
failed\n");
+ printk(KERN_WARNING PFX "ISA PnP activate
failed.\n");
opl3sa2_state[card].activated = 0;
return -ENODEV;
}
------------------------------------------------
-
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