From: Merlijn Wajer <merlijn@xxxxxxxxxx>
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@xxxxxxxxxxx>.
Signed-off-by: Merlijn Wajer <merlijn@xxxxxxxxxx>
Acked-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Bin Liu <b-liu@xxxxxx>
---
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 @@ int musb_mailbox(enum musb_vbus_id_status status)
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 @@ int musb_mailbox(enum musb_vbus_id_status status)
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);
--
1.9.1
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