linux-kernel - Re: USB OOPS 2.6.25-rc2-git1

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Pine.LNX.4.44L0.0802211054550.4528-100000@iolanthe.rowland.org>
Date:	Thu, 21 Feb 2008 10:56:55 -0500 (EST)
From:	Alan Stern <stern@...land.harvard.edu>
To:	David Brownell <david-b@...bell.net>
cc:	Andre Tomt <andre@...t.net>,
	Kernel development list <linux-kernel@...r.kernel.org>,
	USB list <linux-usb@...r.kernel.org>
Subject: Re: USB OOPS 2.6.25-rc2-git1

On Wed, 20 Feb 2008, David Brownell wrote:

> ========= CUT HERE
> Modify EHCI irq handling on the theory that at least some of the
> "lost" IRQs are caused by goofage between multiple lowlevel IRQ
> acking mechanisms:  try rescanning before we exit the handler, in
> case the EHCI-internal ack (by clearing the irq status) doesn't
> always suffice for IRQs triggered nearly back-to-back.
> 
> ---
>  drivers/usb/host/ehci-hcd.c |    8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> --- g26.orig/drivers/usb/host/ehci-hcd.c	2008-02-20 13:26:00.000000000 -0800
> +++ g26/drivers/usb/host/ehci-hcd.c	2008-02-20 13:54:37.000000000 -0800
> @@ -638,6 +638,8 @@ static irqreturn_t ehci_irq (struct usb_
>  		return IRQ_NONE;
>  	}
>  
> +retrigger:
> +
>  	/* clear (just) interrupts */
>  	ehci_writel(ehci, status, &ehci->regs->status);
>  	cmd = ehci_readl(ehci, &ehci->regs->command);
> @@ -725,6 +727,12 @@ dead:
>  
>  	if (bh)
>  		ehci_work (ehci);
> +
> +	status = ehci_readl(ehci, &ehci->regs->status);
> +	status &= INTR_MASK;
> +	if (status)
> +		goto retrigger;
> +
>  	spin_unlock (&ehci->lock);
>  	if (pcd_status & STS_PCD)
>  		usb_hcd_poll_rh_status(hcd);

There's one little problem here.  As a result of this change, the line 
where pcd_status gets set (not shown in this patch) needs to be changed 
to:

		pcd_status |= (status & STS_PCD);

Then the test shown above can be simplified to:

	if (pcd_status)

Alan Stern

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/