Re: git: 575639548cef - main - bus_alloc_resource: Pass rid by value to BUS_ALLOC_RESOURCE DEVMETHOD

On 12/9/25 17:45, Bjoern A. Zeeb wrote:
> On Tue, 9 Dec 2025, John Baldwin wrote:
> 
> Hi,
> 
> upfront: while talking about this very specific change as well, I really just
> want to point out the general problem.
> 
>> On 12/9/25 15:12, John Baldwin wrote:
>>> The branch main has been updated by jhb:
>>>
>>> URL:
>>> https://cgit.FreeBSD.org/src/commit/?id=575639548cef58590a1d70c29e47aae0e8d44153
>>>
>>> commit 575639548cef58590a1d70c29e47aae0e8d44153
>>> Author:     John Baldwin <jhb@FreeBSD.org>
>>> AuthorDate: 2025-12-09 19:59:21 +0000
>>> Commit:     John Baldwin <jhb@FreeBSD.org>
>>> CommitDate: 2025-12-09 20:00:06 +0000
>>>
>>>       bus_alloc_resource: Pass rid by value to BUS_ALLOC_RESOURCE DEVMETHOD
>>>            The wrapper functions such as bus_alloc_resource_any() still
>>> support
>>>       passing the rid by value or pointer, but the underlying implementation
>>>       now passes by value.
>>>            Reviewed by:    imp
>>>       Differential Revision:  https://reviews.freebsd.org/D53402
>>
>> FYI, this breaks the build of drm-kmod (hence the __FreeBSD_version bump).
>> I will open a PR against drm-kmod shortly, but it will still take some time
>> for the patch to make its way into ports.  There's not really a great way
>> to stage changes that depend on __FreeBSD_version bumps. :(
> 
> Yes, it is a pain.
> 
> The version check needs to go in for multiple different branches but likely also
> needs to be applied to ports via patch file as at least one is based on a tag and
> not on a branch currently for as much as I remember.   Just saying as I ran into
> all the tiny details with my previous PCI cleanup there, which cost me a delay of
> more than 2 months to get things in (and then still broke nvidia graphics and
> networking).  Even if not a graphics person, I'll be happy to review this.
> 
> 
> That said, I believe, what I had said before, the proper solution [for this
> specific case] would have been to implement pci_bus_alloc_resource() in LinuxKPI
> and get rid of the FreeBSD specific native code.

Eh, even the Linux code is special in this case as it is allocating a non-standard
BAR.  We do support non-standard BARs (and don't require manually dinking with the
register the way Linux does), and I have a patch to vga_pci to permit
allocating those, but that needs a larger patch and more testing by someone with
old enough hardware to test this case, and in general none of the drm-kmod folks
ever replied on any of those reviews despite multiple pings, so I just went with
the simpler approach.

-- 
John Baldwin