Re: Adaptec-2920 eats too much cpu time when reading from the CD-ROM

[Alan Cox]

> I have recently purchased a Plextor 12x CD-RW and I have attached it to
> and Adaptec-2920 SCSI card. The card uses the "Future Domain Corp. TMC-18C30
> [36C70]" chip.
> 
> The problem I see: when reading from the CD-RW my system becomes very
> unresponsive and top reveals 90-95% of the time is spent on "system".
> My CPU is AMD K6-III/500MHz with 256 Mb RAM.

I'd expect that. The 2920 is pretty old. It has no DMA channel and several
processes it must perform are polled not interrupt driven.

>    scsi1: <fdomain> No BIOS; using scsi id 7
>    scsi1: <fdomain> TMC-36C70 (PCI bus) chip at 0xdc00 irq 10
>    Bad boy: fdomain (at 0xd08b7866) called us without a dev_id!

The Bad boy: line is fixable tho.. This should do it - let me know if it 
makes that one go away.

--- linux.gamma/drivers/scsi/fdomain.h	Sat Nov 17 20:47:53 2001
+++ linux.ac/drivers/scsi/fdomain.h	Thu Dec  6 10:14:51 2001
@@ -43,6 +43,7 @@
 		       abort:          fdomain_16x0_abort,               \
 		       reset:          fdomain_16x0_reset,               \
 		       bios_param:     fdomain_16x0_biosparam,           \
+		       release:        fdomain_16x0_release,		 \
 		       can_queue:      1, 				 \
 		       this_id:        6, 				 \
 		       sg_tablesize:   64, 				 \
--- linux.gamma/drivers/scsi/fdomain.c	Sat Nov 17 20:47:53 2001
+++ linux.ac/drivers/scsi/fdomain.c	Thu Dec  6 10:15:08 2001
@@ -983,7 +983,7 @@
       /* Register the IRQ with the kernel */
 
       retcode = request_irq( interrupt_level,
-			     do_fdomain_16x0_intr, pdev?SA_SHIRQ:0, "fdomain", NULL);
+			     do_fdomain_16x0_intr, pdev?SA_SHIRQ:0, "fdomain", shpnt);
 
       if (retcode < 0) {
 	 if (retcode == -EINVAL) {
@@ -2033,6 +2033,15 @@
    }
    
    return 0;
+}
+
+int fdomain_16x0_release(struct Scsi_Host *shpnt)
+{
+	if (shpnt->irq)
+		free_irq(shpnt->irq, shpnt);
+	if (shpnt->io_port && shpnt->n_io_port)
+		release_region(shpnt->io_port, shpnt->n_io_port);
+
 }
 
 MODULE_LICENSE("GPL");