arch/mips/au1000/common/irq.c

arch/mips/au1000/common/irq.c

[Jeff Baitis]

Pete:

I've got a question concerning irq.c. In intc0_req0_irqdispatch() (linux_2_4
branch) on lines 545 thru 552, the code reads:

      for (i=0; i<32; i++) {
          if ((intc0_req0 & (1<<i))) {
              intc0_req0 &= ~(1<<i);
              do_IRQ(irq, regs);
              break;
          }
          irq++;
      }

My question is: why do we increment i and irq independently?
Why doesn't the code read:

      for (i=0; i<32; i++) {
          if ((intc0_req0 & (1<<i))) {
              intc0_req0 &= ~(1<<i);
              do_IRQ(i, regs);
              break;
          }
      }

Thanks for your help!

-Jeff





-- 
         Jeffrey Baitis - Associate Software Engineer

                    Evolution Robotics, Inc.
                     130 West Union Street
                       Pasadena CA 91103

 tel: 626.535.2776  |  fax: 626.535.2777  |  baitisj@evolution.com 

Re: arch/mips/au1000/common/irq.c

[Dan Malek]

Jeff Baitis wrote:

> Pete:
> 
> I've got a question concerning irq.c. In intc0_req0_irqdispatch() (linux_2_4
> branch) on lines 545 thru 552, the code reads:

I'm hacking these functions to use 'clz' and for other updates, so
the code will be changing soon, anyway :-)  Comment on the next version :-)

Thanks.


	-- Dan

Re: arch/mips/au1000/common/irq.c

[Jeff Baitis]

Dan:

I just verified that I get an IRQ storm when I plug a 3.3-volt based SMC
EPIC/100 network card into the PCI slot of the Au1500. Before I bring the
interface up, I notice that the driver tries to allocate IRQ 1 (INTA). This is
the same IRQ that the ill-fated CardBus bridge attempts to use. ;)

As soon as I bring the SMC interface up using ifconfig (and have the interface
plugged into an active Ethernet network), the IRQ storm ensues.

I'll try Hartvig's patch, look over the irq.c levels, and see how everything
fares.

Thanks all!

Regards,

Jeff


On Thu, Mar 13, 2003 at 01:50:46PM -0500, Dan Malek wrote:
> Jeff Baitis wrote:
> 
> > Pete:
> > 
> > I've got a question concerning irq.c. In intc0_req0_irqdispatch() (linux_2_4
> > branch) on lines 545 thru 552, the code reads:
> 
> I'm hacking these functions to use 'clz' and for other updates, so
> the code will be changing soon, anyway :-)  Comment on the next version :-)
> 
> Thanks.
> 
> 
> 	-- Dan
> 
> 
> 

-- 
         Jeffrey Baitis - Associate Software Engineer

                    Evolution Robotics, Inc.
                     130 West Union Street
                       Pasadena CA 91103

 tel: 626.535.2776  |  fax: 626.535.2777  |  baitisj@evolution.com 

Re: arch/mips/au1000/common/irq.c

[Jeff Baitis]

Hartvig's patch has solved my IRQ storm problems. Thank you all very much for
your attention!

Regards,

Jeff


On Thu, Mar 13, 2003 at 02:13:31PM -0800, Jeff Baitis wrote:
> Dan:
> 
> I just verified that I get an IRQ storm when I plug a 3.3-volt based SMC
> EPIC/100 network card into the PCI slot of the Au1500. Before I bring the
> interface up, I notice that the driver tries to allocate IRQ 1 (INTA). This is
> the same IRQ that the ill-fated CardBus bridge attempts to use. ;)
> 
> As soon as I bring the SMC interface up using ifconfig (and have the interface
> plugged into an active Ethernet network), the IRQ storm ensues.
> 
> I'll try Hartvig's patch, look over the irq.c levels, and see how everything
> fares.
> 
> Thanks all!
> 
> Regards,
> 
> Jeff
> 
> 
> On Thu, Mar 13, 2003 at 01:50:46PM -0500, Dan Malek wrote:
> > Jeff Baitis wrote:
> > 
> > > Pete:
> > > 
> > > I've got a question concerning irq.c. In intc0_req0_irqdispatch() (linux_2_4
> > > branch) on lines 545 thru 552, the code reads:
> > 
> > I'm hacking these functions to use 'clz' and for other updates, so
> > the code will be changing soon, anyway :-)  Comment on the next version :-)
> > 
> > Thanks.
> > 
> > 
> > 	-- Dan
> > 
> > 
> > 
> 
> -- 
>          Jeffrey Baitis - Associate Software Engineer
> 
>                     Evolution Robotics, Inc.
>                      130 West Union Street
>                        Pasadena CA 91103
> 
>  tel: 626.535.2776  |  fax: 626.535.2777  |  baitisj@evolution.com 
> 
> 

-- 
         Jeffrey Baitis - Associate Software Engineer

                    Evolution Robotics, Inc.
                     130 West Union Street
                       Pasadena CA 91103

 tel: 626.535.2776  |  fax: 626.535.2777  |  baitisj@evolution.com 

Re: arch/mips/au1000/common/irq.c

[Pete Popov]

On Thu, 2003-03-13 at 10:47, Jeff Baitis wrote:
> Pete:
> 
> I've got a question concerning irq.c. In intc0_req0_irqdispatch() (linux_2_4
> branch) on lines 545 thru 552, the code reads:
> 
>       for (i=0; i<32; i++) {
>           if ((intc0_req0 & (1<<i))) {
>               intc0_req0 &= ~(1<<i);
>               do_IRQ(irq, regs);
>               break;
>           }
>           irq++;
>       }
> 
> My question is: why do we increment i and irq independently?
> Why doesn't the code read:
> 
>       for (i=0; i<32; i++) {
>           if ((intc0_req0 & (1<<i))) {
>               intc0_req0 &= ~(1<<i);
>               do_IRQ(i, regs);
>               break;
>           }
>       }
> 
> Thanks for your help!

No reason. It was probably more clear to me when writing the code and
later I didn't look for such improvements. Like Dan said though, he's
updating/optimizing that part of the code anyway ...

Pete