Device enumeration support in libdrm

[Zhou, Jammy]

Although I don't like the method of manually iterating sysfs, it seems the last resort if we want to avoid introducing libudev dependency.

Besides, you mentioned that you would spend some time on the device enumeration interface, do you have some chance to look at it?

Regards,
Jammy

-----Original Message-----
From: Emil Velikov [mailto:emil.l.velikov at gmail.com] 
Sent: Thursday, July 09, 2015 12:25 AM
To: Zhou, Jammy
Cc: dri-devel at lists.freedesktop.org
Subject: Re: Device enumeration support in libdrm

Hello Jammy,

On 8 July 2015 at 06:53, Zhou, Jammy <Jammy.Zhou at amd.com> wrote:
> Hi Emil,
>
>
>
> With our previous RFC patches to add interfaces to support GPU device 
> enumeration support in libdrm, the udev mechanism was used. But we 
> found that if we introduce the libudev dependency for libdrm, there 
> will be some problem to run steam application on recent distributions 
> (for example, Ubuntu 14.04 LTS) because of the conflict between the 
> system libudev.so.1 (loaded by libdrm) and the libudev.so.0 (bundled 
> in steam-runtime and loaded by steam application). There are some 
> similar issues as mentioned in the links below. Although we can argue 
> that it is application’s problem, can we get rid of libudev for the 
> device enumeration before Valve can make steam-runtime use system 
> libraries by default? It is much appreciated if you can give some 
> suggestions about how we can support device enumeration with libdrm.
>
I believe I mentioned it before, perhaps I wasn't clear enough. Rather than using libudev, manually iterate through sysfs. I agree it's not a not pretty solution yet the libdrm code already has much weirder stuff.

Cheers
Emil