Re: [edk2-devel] [PATCH] MdeModulePkg/NonDiscoverablePciDeviceDxe: connect handles on registration

["Ard Biesheuvel" <ard.biesheuvel@arm.com>]

On 5/22/20 6:48 PM, Laszlo Ersek wrote:
> On 05/22/20 18:46, Laszlo Ersek wrote:
> 
>> the spec led me to believe
> 
> Well, if I had read a few more pages from the spec... It's totally my
> fault! :) sorry, it's Friday! :)
> 


No worries, thanks for taking the time to dig into this.

I had already noticed that the DriverImageHandle[] approach does not 
work, it indeed simply changes the order in which drivers are considered.

So I found a way to fix this in the BDS, which is not as clean as I 
like, but not that intrusive either. It turns out the the existing code 
plays nicely with the driver model in most cases, the only place where 
it cuts corners is when it connects the short-form USB device path for 
the console keyboard - this is the only place where it mucks around with 
PCI I/O handles explicitly, to connect USB host controllers.

So we can simply do the same for non-discoverable uhci/ehci/xhci 
devices, i.e., connect them non-recursively so that the PCI I/O protocol 
as well as the USB host controller protocol are installed (which is 
fine, as the latter was going to be installed by the BDS anyway)