Messages in this thread Patch in this message | | | From | Merlijn Wajer <> | Subject | [PATCH v2 1/1] usb: musb: call pm_runtime_{get,put}_sync before reading vbus registers | Date | Tue, 27 Feb 2018 23:27:39 +0100 |
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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 | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c index eef4ad578b31..c344ef4e5355 100644 --- a/drivers/usb/musb/musb_core.c +++ b/drivers/usb/musb/musb_core.c @@ -1756,6 +1756,7 @@ vbus_show(struct device *dev, struct device_attribute *attr, char *buf) int vbus; u8 devctl; + pm_runtime_get_sync(dev); spin_lock_irqsave(&musb->lock, flags); val = musb->a_wait_bcon; vbus = musb_platform_get_vbus_status(musb); @@ -1769,6 +1770,7 @@ vbus_show(struct device *dev, struct device_attribute *attr, char *buf) vbus = 0; } spin_unlock_irqrestore(&musb->lock, flags); + pm_runtime_put_sync(dev); return sprintf(buf, "Vbus %s, timeout %lu msec\n", vbus ? "on" : "off", val); -- 2.16.2
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