Messages in this thread | | | Subject | Re: [RFC PATCH] usb: musb: call pm_runtime_{get,put}_sync before reading vbus registers | From | Sergei Shtylyov <> | Date | Sun, 25 Feb 2018 12:01:46 +0300 |
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Hello!
On 2/24/2018 11:51 PM, Merlijn Wajer wrote:
> Without pm_runtime_{get,put}_sync calls in place, reading > vbus status via /sys causes the following error: > > Unhandled fault: external abort on non-linefetch (0x1028) at 0xfa0ab060 > pgd = b333e822 > [fa0ab060] *pgd=48011452(bad) > > [<c05261b0>] (musb_default_readb) from [<c0525bd0>] (musb_vbus_show+0x58/0xe4) > [<c0525bd0>] (musb_vbus_show) from [<c04c0148>] (dev_attr_show+0x20/0x44) > [<c04c0148>] (dev_attr_show) from [<c0259f74>] (sysfs_kf_seq_show+0x80/0xdc) > [<c0259f74>] (sysfs_kf_seq_show) from [<c0210bac>] (seq_read+0x250/0x448) > [<c0210bac>] (seq_read) from [<c01edb40>] (__vfs_read+0x1c/0x118) > [<c01edb40>] (__vfs_read) from [<c01edccc>] (vfs_read+0x90/0x144) > [<c01edccc>] (vfs_read) from [<c01ee1d0>] (SyS_read+0x3c/0x74) > [<c01ee1d0>] (SyS_read) from [<c0106fe0>] (ret_fast_syscall+0x0/0x54) > > Solution was suggested by Tony Lindgren <tony@atomide.com>. > > Signed-off-by: Merlijn Wajer <merlijn@wizzup.org> > --- > drivers/usb/musb/musb_core.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c > index ea5013aa69e2..182611f76af3 100644 > --- a/drivers/usb/musb/musb_core.c > +++ b/drivers/usb/musb/musb_core.c [...] > @@ -1767,6 +1769,9 @@ musb_vbus_show(struct device *dev, struct device_attribute *attr, char *buf) > vbus = 1; > else > vbus = 0; > + > + pm_runtime_put_sync(dev); > +
Empty line not needed here.
> } > spin_unlock_irqrestore(&musb->lock, flags); >
MBR, Sergei
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