Hi Clemens, Thanks for putting this together. I'm not sure if I'll have time to look at it this week, and I'm leaving for a conference on Friday. So if you don't hear from me it's not because I hate the patches. :) Sarah Sharp On Mon, Jun 21, 2010 at 01:57:31PM +0200, Clemens Ladisch wrote: > (Sorry for the delay.) > Sarah Sharp wrote: > > On Wed, Jun 09, 2010 at 11:16:10AM +0200, Clemens Ladisch wrote: > > > MSI is just a minor variation of a normal interrupt, but [my old patch] > > > cannot handle MSI-X as it isn't known how many interrupts are acceptable, > > > or what the dev parameters in the request_irq() calls should be. > > > > Hmm, why not add new API in the same spot to ask the host how many MSI-X > > interrupters it can support? If it says zero, then you can see if it > > supports MSI with a call to is_pci_msi_allowed(). > > The kernel might not be able to allocate that many interrupts, so in > theory, the pci_enable_msi(x) calls belong into the HCD so that the > driver can negotiate with the kernel how many interrupts to actually > use. > > > > It appears that common MSI code is easy, but that implementing MSI-X > > > still requires replacing most of the generic hcd interrupt handling code > > > (either with a callback or by replacing the interrupt later). > > > > Perhaps the HCD could provide an MSI/MSI-X call back function? That > > would fit with Dong's current patch. > > Yes, the HC driver should be able to decide whether to use MSI-X or MSI. > > > There's also issues with mapping IRQ to internal data structures. The > > xHCI host is going to need to be able to map the irq number for the > > MSI-X vector into a specific event ring that needs to be serviced. > > If the HCD does the request_irq calls by itself, it can just use > whatever dev parameter it likes. I've decided not to add another > callback but to leave this code in the start callback. > > > These patches are on top of Dong's; the xHCI stuff is untested. > > > drivers/usb/core/hcd-pci.c | 36 +++++++-- > drivers/usb/core/hcd.c | 5 - > drivers/usb/host/ehci-pci.c | 72 ++++++++++++++++-- > drivers/usb/host/ohci-pci.c | 51 +++++++++++++ > drivers/usb/host/xhci-pci.c | 83 +++++++++++++++++++++ > drivers/usb/host/xhci.c | 137 +++++------------------------------- > include/linux/usb/hcd.h | 11 ++ > 7 files changed, 258 insertions(+), 137 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
