Date: Sat, 3 Oct 2009 09:53:16 +0200 From: Hans Petter Selasky <hselasky@c2i.net> To: freebsd-current@freebsd.org Subject: Re: [PATCH] Fix for USB media not found at boot Message-ID: <200910030953.17359.hselasky@c2i.net> In-Reply-To: <20091002150931.K35591@pooker.samsco.org> References: <20091002150931.K35591@pooker.samsco.org>
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On Friday 02 October 2009 23:11:21 Scott Long wrote:
> All,
>
> I have a candidate patch to fix the problem with USB boot media not being
> found in time at boot, leading to the "mountroot" prompt instead of a
> booting system. Please apply both patches below and let me know if it
> works for you.
Hi,
Your patch looks OK. Some checkpoints however:
Does your patch work if ehci/ohci/uhci is kldloaded after system startup?
Does your patch work if CAM is not in the kernel?
I have a simple imporovement to your patch:
I would just add a synchronously blocking call to the end of "usb_bus_attach".
Something like:
#ifdef USB_HAVE_CAM
static void
usb_cam_wait_cb(void *arg)
{
struct usb_bus *bus = *(struct usb_bus **)arg;
USB_BUS_LOCK(bus);
*(struct usb_bus **)arg = NULL;
wakeup(arg);
USB_BUS_UNLOCK(bus);
}
static void
usb_wait_cam(struct usb_bus *bus)
{
struct intr_config_hook *hook;
void *temp = bus;
hook = malloc(sizeof(*hook), M_TEMP, M_ZERO);
hook->ich_func = usb_wait_cam_cb;
hook->ich_arg = &temp;
config_intrhook_establish(hook);
USB_BUS_LOCK(bus);
if (temp != NULL)
mtx_sleep(&temp, &bus->bus_mtx, 0, "WCAM", 0);
USB_BUS_UNLOCK(bus);
}
#endif
That way makes the code more simple and avoids a race with the CAM callback
being called after that the hardware is detached. For example if the Host
Controller resides on a removable device.
There are some more USB_HAVE_XXX in sys/dev/usb/usb_freebsd.h .
--HPS
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