Re: [RFC v3] Add support for Sony PS2 OHCI

[Fredrik Noring]

Hi Alan Stern,

> > > What happened to the changes to ohci_run() and ohci_irq() that were in 
> > > v2 of this RFC?  Did you decide they weren't needed?
> > 
> > In v3 Jürgen Urban folded those changes into the driver functions
> > 
> >     ohci_ps2_enable(),
> >     ohci_ps2_disable(),
> >     ohci_ps2_start_hc() and
> >     ohci_ps2_stop_hc()
> > 
> > in drivers/usb/host/ohci-ps2.c.
> 
> Good, I was going to suggest doing that.

There is one quirk with the ISR that perhaps could be clarified: For some
reason we have to intercept ohci_irq to disable interrupts, as shown in the
function below, otherwise the whole USB subsystem eventually will freeze up.

Is this a known OHCI problem? Is some part of its USB core ISR not reentrant?

static irqreturn_t ohci_ps2_irq(struct usb_hcd *hcd)
{
        struct ohci_hcd *ohci = hcd_to_ohci(hcd);
        struct ohci_regs __iomem *regs = ohci->regs;

        /*
         * FIXME: For some reason OHCI_INTR_MIE is required in the
         * IRQ handler. Without it, reading a large amount of data
         * (> 1 GB) from a mass storage device results in a freeze.
         */
        ohci_writel(ohci, OHCI_INTR_MIE, &regs->intrdisable);

        return ohci_irq(hcd); /* Call normal IRQ handler. */
}

Fredrik
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