4.4-stable review patch. If anyone has any objections, please let me know.
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From: Merlijn Wajer merlijn@wizzup.org
[ Upstream commit df6b074dbe248d8c43a82131e8fd429e401841a5 ]
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 Acked-by: Tony Lindgren tony@atomide.com Signed-off-by: Bin Liu b-liu@ti.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/musb/musb_core.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/usb/musb/musb_core.c +++ b/drivers/usb/musb/musb_core.c @@ -1775,6 +1775,7 @@ musb_vbus_show(struct device *dev, struc 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); @@ -1788,6 +1789,7 @@ musb_vbus_show(struct device *dev, struc 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);