Messages in this thread | | | Date | Fri, 10 Jan 2003 11:00:30 -0800 | Subject | Re: [patch 2.5] 2-pass PCI probing, generic part | From | (Grant Grundler) |
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On Fri, Jan 10, 2003 at 12:56:17AM -0700, Eric W. Biederman wrote: > For what it is worth these cards exist though.
yes.
> Quadris cards have a 256MB bar, and dolphin cards default to having a 512MB bar. > Both are high performance I/O adapters.
I'm not familiar with "dolphin" cards. I'm aware of "Quadrics" but I've not heard anyone try those with parisc-linux. Quadrics cards do work on ia64 (for some definition of "work").
> If someone leaves a big enough hole for hotplug cards I guess it can work...
Or dynamically assigns windows to PCI Bus controllers as PCI devices are brought on-line. For PCI Hotplug, the role of managing MMIO/IRQ resources has moved to the OS since these services are needed after the OS has taken control of the box.
> How you define a potential boot device, and what it saves you to not assign > it resources I don't know.
You have it backwards. firmware only assigns resources to boot devices and "console" devices. ie firmware does minimal configuration. Why? An OS with hotplug support can do it anyway.
A "potential boot device" has firmware support which the primary boot loader can use to load the OS or a secondary boot loader. But firmware only needs to configure a single boot/console device that is actually being used.
> I am still recovering from putting a 256MB bar and 4GB of ram in a 4GB hole, > with minimal loss on x86, so my imagination of what can be sanely done > on a 64bit arch may be a little stunted..
both ia64 and later parisc boxes from HP reserve GB's of LMMIO address space for IO uses (LMMIO == MMIO < 4GB). AFAIK, physical memory behind that address space gets remapped to higher "physical" addresses by the memory controller. But making 256MB still fit in that space can still be a challenge. One 256MB BAR isn't so bad. It's when the customer wants to have a central server that has 2 or more such cards...64-bit BARs on 64-bit architecture make life alot easier.
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