Re: Rework of request firmware

[Kay Sievers <kay.sievers@vrfy.org>]

On Sun, 2005-03-20 at 10:35 -0500, Jon Smirl wrote:
> On Sun, 20 Mar 2005 14:37:16 +0100, Kay Sievers <kay.sievers@vrfy.org> wrote:
> > What is the concept of a "post"? Does it receive data for the kernel to
> > use? What is the overlap with firmware loading here? You just need to
> > run a program from userspace, right?
> 
> Post is the commonly used term for what you do to hardware when it is
> first turned on to get it running. For example the system BIOS posts
> all the devices in the system.

Ok, the Power On Self Test. That sounds a bit specfic for something that
is a generic configuration request.

> The system BIOS does not post secondary video cards. For these cards
> when the driver is first loaded I have to run a program that takes the
> video BIOS ROM on the card and runs it in vm86/emu86. The ROM contents
> are already exposed in sysfs. If I don't do this the hardware will not
> respond. The system BIOS does this for you in real mode on the primary
> card during the boot process. Another time the video BIOS needs to be
> run is when graphics cards are being resumed. The posting program
> needs to run in user space and be triggered from the probe function.

Ah, ok. Sounds reasonable and like a nice trick too, to run x86 hardware
on other platforms. :)

> I initially started to add support for post as a standalone service
> but received complaints on lkml that the code needed was almost
> identical to request_firmware(). 

Well running a configuration program is just a very small subset
compared to copying data into the kernel, but anyway...

> BenH has also pointed out that the
> synchronous request_firmware() will deadlock in many cases during the
> resume process.

I believe that and events may get lost too in such situations.

Thanks,
Kay



-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_ide95&alloc_id\x14396&op=click
_______________________________________________
Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel