From mboxrd@z Thu Jan 1 00:00:00 1970 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 Message-ID: <20180227222740.2150-2-merlijn@wizzup.org> References: <20180227222740.2150-1-merlijn@wizzup.org> Return-path: In-Reply-To: <20180227222740.2150-1-merlijn@wizzup.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-omap@vger.kernel.org Cc: tony@atomide.com, merlijn@wizzup.org, Bin Liu , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-omap@vger.kernel.org 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) [] (musb_default_readb) from [] (musb_vbus_show+0x58/0xe4) [] (musb_vbus_show) from [] (dev_attr_show+0x20/0x44) [] (dev_attr_show) from [] (sysfs_kf_seq_show+0x80/0xdc) [] (sysfs_kf_seq_show) from [] (seq_read+0x250/0x448) [] (seq_read) from [] (__vfs_read+0x1c/0x118) [] (__vfs_read) from [] (vfs_read+0x90/0x144) [] (vfs_read) from [] (SyS_read+0x3c/0x74) [] (SyS_read) from [] (ret_fast_syscall+0x0/0x54) Solution was suggested by Tony Lindgren . Signed-off-by: Merlijn Wajer --- 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