[PATCH 0/3] drm/exynos: Allow module to be autoloaded

[Inki Dae]

On 2014년 07월 29일 20:59, Andreas Färber wrote:
> Am 29.07.2014 10:05, schrieb Sjoerd Simons:
>> On Tue, 2014-07-29 at 14:38 +0900, Inki Dae wrote:
>>> On 2014년 07월 28일 23:45, Sjoerd Simons wrote:
>>>> On Mon, 2014-07-28 at 23:17 +0900, Inki Dae wrote:
>>>>> On 2014년 07월 28일 17:30, Sjoerd Simons wrote:
>>>>> I don't see why Exynos drm driver should be auto-loaded module. I think
>>>>> all devices covered by Exynos drm framework are not hot-plugged. Maybe
>>>>> there is my missing point. So can you explain why Exynos drm driver
>>>>> should be auto-loaded module?
>>>>
>>>> The background for this is that I'm building a distribution-style
>>>> multiplatform kernel, that is to say a kernel which can boot on a big
>>>> set of different ARM boards. As such, the intention is to keep the core
>>>> zImage as small as possible and essentially build things as far as
>>>> possible as loadable modules. So in a sense, all of the hardware is
>>>> "hotplugged", depending on which board the kernel is actually booted on!
>>>>
>>>> For that use-case, exynosdrm needs to be able to build as a module
>>>> (which it already can!) and it needs the required meta-data for
>>>> userspace to know when it should be loaded. The latter is what my patch
>>>> adds. 
>>>
>>> It seems that you want that module data of sub drivers are added by
>>> depmod to /lib/modules/KERNEL_VERSION/modules.xxxmap because some
>>> hot-plug system should use modules.xxxmap file to find the proper driver
>>> to load.
>>
>> Yes. I would like the module to export its module alias information for
>> the subdrivers such that depmod can add it to its databases and the
>> normal module autoloading mechanisms work as intended. Note that in my
>> case, "some hot-plug" system is really just udev, not something
>> special..
> 
> +1 here.
> 
> While I haven't tested this on my Exynos devices yet since I'm still
> working on -next kernels there, here's an example of such a 3.16 config:
> 
> http://kernel.opensuse.org/cgit/kernel-source/tree/config/armv7hl/default
> 
> Of the platforms enabled, all drivers are configured as modules where
> possible, to keep kernel size small, and dracut (or kiwi) is used to
> generate an initrd that makes available the modules.
> 
> So it would certainly be good to have the DRM auto-load somehow, without
> the user having to manually touch config files. In particular when I
> think of the Chromebooks, where Wifi needs configuration on first boot
> and no serial console is accessible.

Got it. will merge them. However, I'm not sure that Exynos drm should
have hot-plug feature such as PCI base devices: all devices covered by
Exynos drm framework cannot attached and detached to and from machine.

Thanks,
Inki Dae



> 
> Regards,
> Andreas
>