Re: Network drivers that don't suspend on interface down

On Thu, 2006-12-21 at 02:18 +0000, Matthew Garrett wrote:
On Wed, Dec 20, 2006 at 09:05:27PM -0500, Michael Wu wrote:

Softmac isn't the only wireless code that likes to be configured after going
up first. Configuring after the card goes up has generally been more
reliable, though that should not be necessary and is a bug IMHO.

Ok, that's nice to know.

In order to scan, we need to have the radio on and we need to be able to send
and receive. What are you gonna turn off?

The obvious route would be to power the card down, but come back up
every two minutes to perform a scan, or if userspace explicitly requests
one. Would this cause problems in some cases?

Seriously, having all these different capabilities when the card is
"down" is just madness. Down == Down!!! Furthermore, every card is
going to support some other subset of capabilities when it's "down".
When you bring "up" prism54 fullmac card, you have to power up the
hardware, reload the firmware, let the firmware boot, and then talk to
it. Doing that every 2 minutes is just a waste of time, effort, and
power.

If you want to scan, just bring the darn card up to do it. It's so much
simpler that way, and I just don't see what having all this "every 2
minutes do a scan" policy really buys us. That doesn't belong in the
kernel. If something wants to scan, userspace can wake the card up and
do the scan. It's userspace that's using the scan results to configure
the card anyway, so userspace can do the scan.

Simple == good. Down == down. Lets just agree on that and save
ourselves a lot of pain.

Dan


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Relevant Pages

  • Re: Network drivers that dont suspend on interface down
    ... so I fail to see where userspace could expect to do anything ... with a wireless card when it's down too. ... Because it works on the common hardware? ...
    (Linux-Kernel)
  • Re: Network drivers that dont suspend on interface down
    ... You can't get link events for many wired cards when they ... so I fail to see where userspace could expect to do anything ... with a wireless card when it's down too. ... But in the absence of any indication as to what functionality users can ...
    (Linux-Kernel)
  • Re: [2.6.22-rc3][ACPI?] Resume from s2r doesnt work.
    ... I'm still suspecting that the problem is related to your graphics adapter. ... Maybe it's the most common problem, but why do you think so? ... a black screen the kernel should return to userspace. ... Still, if the card is a 7300 or higher, that need not work (at present we don't ...
    (Linux-Kernel)
  • Re: [GIT PATCH] more Driver core patches for 2.6.19
    ... validation of the commands that are sent to the card. ... isolation-capable IOMMU, so if you let userspace program it, you need ... Userspace IO was never intended to replace all kinds of possible ... This is possible with a standard kernel and is done ...
    (Linux-Kernel)
  • Re: InterVideo XPack 2009 vs. Nvidia MCE 2005 XP Codec packs MVPs?
    ... 1GB ATI Radeon HD-3650. ... Otherwise it's a great card if you don't play DVDs. ... resolution source and then how much power does it require to do it. ... Driver Date 1/14/2009. ...
    (microsoft.public.windows.mediacenter)