Hi, On 25-Jun-25 4:33 PM, Lukas Wunner wrote: > On Wed, Jun 25, 2025 at 04:08:38PM +0200, Hans de Goede wrote: >> Lukas made me aware of this attempt to fix the KERN_CRIT msg, because >> I wrote a slightly different patch to fix this: >> >> https://lore.kernel.org/dri-devel/20250625112411.4123-1-ha...@kernel.org/ >> >> This seems like a cleaner fix to me and something which would be good >> to have regardless since currently the driver_attach() call is doing >> too much work because the promisc table catches an unnecessary wide >> net / match matching many PCI devices which cannot be AGP capable >> at all. > > So how do you know that all of these unsupported devices have > PCI_CLASS_BRIDGE_HOST?
The top of the driver says * This is a GART driver for the AMD Opteron/Athlon64 on-CPU northbridge. * It also includes support for the AMD 8151 AGP bridge Note this only talks about north bridges. Also given the age of AGP, I would expect the agp_amd64_pci_table[] to be pretty much complete and the need for probing for unknown AGP capable bridges is likely a relic which can be disabled by default. Actually the amd64-agp code is weird in that has support for unknown AGP bridges enabled by default in the first place. The global probe unknown AGP bridges bool which is called agp_try_unsupported_boot is false by default. As discussed in the thread with my patch, we should probably just change the AMD specific agp_try_unsupported to default to false too. > The only thing we know is that an AGP > Capability must be present. > > In particular, AGP 3.0 sec 2.5 explicitly allows PCI-to-PCI bridges > in addition to Host-to-PCI bridges. Ok, so we can add a second entry to the agp_amd64_pci_promisc_table[] to match PCI to PCI bridges just to be sure, that still feels cleaner to me. Regards, Hans
