From: Merlijn Wajer merlijn@wizzup.org
commit df6b074dbe248d8c43a82131e8fd429e401841a5 upstream.
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.
Cc: stable@vger.kernel.org # v4.9+ Signed-off-by: Merlijn Wajer merlijn@wizzup.org Acked-by: Tony Lindgren tony@atomide.com Signed-off-by: Bin Liu b-liu@ti.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.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 0736cc27b5e7..d4c9e9544ba0 100644 --- a/drivers/usb/musb/musb_core.c +++ b/drivers/usb/musb/musb_core.c @@ -1774,6 +1774,7 @@ 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); @@ -1787,6 +1788,7 @@ 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);