Re: [Q] How to tell we're using the KMS (during suspend/resume) outside the graphics driver

[Luca Tettamanti <kronos.it@gmail.com>]

On Sat, Mar 6, 2010 at 10:36 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> Hi,
>
> For at least two reasons it would be beneficial for some code outisde the
> graphics driver(s) to know if the KMS are used.
>
> First, in the non-KMS (ie. UMS) case we probably wouldn't want to call
> acpi_video_resume(), because that has a potential to mess up with the GPU
> (it actually is known to do that on at least one system).
>
> Second, in the KMS case, we'd be able to skip the kernel VT switch, because
> the KMS driver uses its own framebuffer anyway.
>
> So, is there any reasonable way to check that from the outside of the graphics
> driver?  It should be general enough to cover the cases when there are two
> graphics adapters with different drivers in the system and so forth.

Inside the kernel? If you have a struct pci_dev you can get the
associated struct drm_device with pci_get_drvdata and then check the
KMS feature: drm_core_check_feature(dev, DRIVER_MODESET).
I'm note sure how to check that a device is graphic card though :|

Luca