On Wed, Mar 23, 2022 at 4:26 AM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > On Mon, Mar 21, 2022 at 01:34:46PM -0500, Bjorn Helgaas wrote: > > From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > > > Some ATI SB600 USB adapters advertise MSI, but if INTx is disabled by > > setting PCI_COMMAND_INTX_DISABLE, > > MSI doesn't work either. I think this is not correct. > > The PCI/PCIe > > specs do not require software to set PCI_COMMAND_INTX_DISABLE when enabling > > MSI, but Linux has done that for many years. > > > > Mick reported that 306c54d0edb6 ("usb: hcd: Try MSI interrupts on PCI > > devices") broke these devices. Prior to 306c54d0edb6, they used INTx. > > Starting with 306c54d0edb6, they use MSI, and and the fact that Linux sets > > PCI_COMMAND_INTX_DISABLE means both INTx and MSI are disabled on these > > devices. > > Avoid this SB600 defect by disabling MSI so we use INTx as before. And this is kinda too conservative approach. > > Fixes: 306c54d0edb6 ("usb: hcd: Try MSI interrupts on PCI devices") > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=215690 > > Link: https://lore.kernel.org/all/PxIByDyBRcsbpcmVhGSNDFAoUcMmb78ctXCkw6fbpx25TGlCHvA6SJjjFkNr1FfQZMntYPTNyvEnblxzAZ8a6jP9ddLpKeCN6Chi_2FuexU=@protonmail.com/ > > BugLink: https://lore.kernel.org/all/20200702143045.23429-1-andriy.shevchenko@xxxxxxxxxxxxxxx/ > > Link: https://lore.kernel.org/r/20220314101448.90074-1-andriy.shevchenko@xxxxxxxxxxxxxxx > > Reported-by: Mick Lorain <micklorain@xxxxxxxxxxxxxx> > > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> And it hasn't been tested by the reporter. > Unless there's objection, I plan to include this in the v5.18 pull > request in the next few days. You are the maintainer here and it's your choice. I'm not going to stop you. -- With Best Regards, Andy Shevchenko