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

From: Alan Cox (alan@lxorguk.ukuu.org.uk)
Date: Thu Dec 06 2001 - 04:28:08 EST

> 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");
-
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This archive was generated by hypermail 2b29 : Fri Dec 07 2001 - 21:00:33 EST