On Fri, May 23, 2025 at 07:33:16AM +0200, Lukas Wunner wrote: > On Thu, May 22, 2025 at 06:19:56PM +0200, Niklas Cassel wrote: > > As you know the reset_slot() callback patches were merged recently. > > > > Wilfred and I (mostly Wilfred), have been debugging DMA issues after the > > reset_slot() callback has been invoked. The issue is reproduced when MPS > > configuration is set to performance, but might be applicable for other > > MPS configurations as well. The problem appears to be that reset_slot() > > feature does not respect/restore the MPS configuration. > > The Device Control register (and thus the MPS setting) is saved via: > > pci_save_state() > pci_save_pcie_state() > > So either you're missing a call to pci_restore_state() after reset, > or you're missing a call to pci_save_state() after changing MPS, > or MPS is somehow overwritten after pci_restore_state(). > Which one is it? I kind of liked the earlier revision of Mani's series where we kicked the devices off the bus, that way, we would re-use the exact same code paths as when doing the initial enumeration. Also, by removing the device, the exact same solution works fine both for link-down (since the device might never come back again), and for a sysfs initiated reset. Anyway, I'm happy with whatever solution that works. Adding pci_save_state() + pci_restore_state() seems fine, but since things are not working, I assume that those calls are missing, at least of the bridge. Are we also missing similar pci_save_state() + pci_restore_state() calls for the EP? Kind regards, Niklas
