Hello Mani, On Sat, Nov 30, 2024 at 01:42:45PM +0530, Manivannan Sadhasivam wrote: > > > > struct pci_epf_test { > > @@ -74,6 +76,7 @@ struct pci_epf_test_reg { > > u32 irq_type; > > u32 irq_number; > > u32 flags; > > + u32 caps; > > Can we rename the 'magic' register? It is not used since the beginning and I > don't know if we will ever have a usecase for it. It is actually used! When doing PCITEST_BAR (pci_endpoint_test_bar()), and barno == test->test_reg_bar, we are only filling the first 4 bytes, rather than filling the whole BAR: https://github.com/torvalds/linux/blob/v6.13-rc1/drivers/misc/pci_endpoint_test.c#L293-L294 These first 4 bytes are stored in the magic register. I do agree that the magic register name is slightly misleading, but that seems completely unrelated to this patch. If you can come up with a better name, send a patch and you shall have my Reviewed-by tag :) Kind regards, Niklas