Re: [PATCH 03/13] iommu/mediatek: Add probe_defer for smi-larb

Evan Green
2019-02-25T23:54:00Z

On Mon, Dec 31, 2018 at 8:52 PM Yong Wu <yong.wu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> wrote:
>
> The iommu consumer should use device_link to connect with the
> smi-larb(supplier). then the smi-larb should run before the iommu
> consumer. Here we delay the iommu driver until the smi driver is
> ready, then all the iommu consumer always is after the smi driver.
>
> When there is no this patch, if some consumer drivers run before
> smi-larb, the supplier link_status is DL_DEV_NO_DRIVER(0) in the
> device_link_add, then device_links_driver_bound will use WARN_ON
> to complain that the link_status of supplier is not right.
>

I don't quite have enough knowledge of device links to figure out if
this is a) the right fix, b) a deficiency in the device_links code, or
c) neither.

Perhaps someone else could chime in on this one.
-Evan