Netgear MA301 works

David Gibson david at
Mon Jan 1 11:36:09 EST 2001

On Thu, Nov 15, 2001 at 10:08:49AM +0100, Bjoern Giesler wrote:
> Hi,
> *phew* finally. I got my MA301 working under Linux with the orinoco_plx 
> driver. I use a Lucent/WaveLAN Silver card. The fix was indeed fiddling 
> with the PLX's Interrupt Enable register. Patch (to orinoco-0.08b, from 
> David Gibson's testing directory) attached; it's very small. I haven't 
> tried any encryption, and only Ad-Hoc mode; still, I watched a DivX movie 
> across the wireless link last night, which suggests it's quite stable. 
> One issue remains: On rmmod, some things obviously get corrupted in 
> kernel memory (try cat /proc/interrupts; produces garbage on my machine). 
> I'll look into that.
> But I have a (perhaps PCI-related) question. The PLX's PCI base address 
> registers theoretically have the first one (resource 0) point to 
> memory-accessable memory and the second one (resource 1) point to 
> IO-accessable memory; apart from the access method, both should allow the 
> same local configuration access (see p8-1 of the PLX data book for 
> reference).
> Now, the first one points to 0; accordingly, pci_resource_start(dev, 0) 
> returns 0x0. So that probably means that no memory access is possible to 
> the local config. So far, so good; if we're supposed to do inb/outb, we 
> can. But if I don't check for 0-ness of that address, and just pass it to 
> ioremap(), I get a valid adress back! (Which is, of course, bogus -- I 
> don't want to know whose driver space I fiddled with when that happened 
> to me.) Is this by design, or is it a bug in ioremap()?

ioremap() has no way to tell that the address is invalid - it doesn't
understand PCI itself.  It will just set up a virtual mapping to the
specified physical address.  Physical address zero will probably
correspond to the beginning of RAM.

David Gibson			| For every complex problem there is a
david at	| solution which is simple, neat and
				| wrong.  -- H.L. Mencken

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