Hello. On 12/4/2014 3:06 PM, Thierry Reding wrote:
From: Thierry Reding <treding@xxxxxxxxxx>
Commit 1290a958d48e ("usb: phy: propagate __of_usb_find_phy()'s error on failure") broke platforms that rely on deferred probing to order probing of PHY and host controller drivers. The reason is that the commit simply propagates errors from __of_usb_find_phy(), which returns -ENODEV if no PHY has been registered yet for a given device tree node. The only case in which -EPROBE_DEFER would now be returned is if try_module_get() did fail, which does not make sense.
The correct thing to do is to return -EPROBE_DEFER if a PHY hasn't been registered yet. The only condition under which it makes sense to return -ENODEV is if the device tree node representing the PHY has been disabled (via the status property) because in that case the PHY will never be registered.
This patch addresses the problem by making __of_usb_find_phy() return an appropriate error code while keeping in line with the above-mentioned commit to propagate error codes rather than overwriting them. At the same time the check for a valid PHY is decoupled from the check for the try_module_get() call and a separate error code is returned if the latter fails.
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx> --- drivers/usb/phy/phy.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/phy/phy.c b/drivers/usb/phy/phy.c index b4066a001ba0..2f9735b35338 100644 --- a/drivers/usb/phy/phy.c +++ b/drivers/usb/phy/phy.c
[...]
@@ -190,10 +193,13 @@ struct usb_phy *devm_usb_get_phy_by_phandle(struct device *dev, spin_lock_irqsave(&phy_lock, flags); phy = __of_usb_find_phy(node); - if (IS_ERR(phy) || !try_module_get(phy->dev->driver->owner)) { - if (!IS_ERR(phy)) - phy = ERR_PTR(-EPROBE_DEFER); + if (IS_ERR(phy)) { + devres_free(ptr); + goto err1; + } + if (!try_module_get(phy->dev->driver->owner)) { + phy = ERR_PTR(-ENODEV); devres_free(ptr); goto err1; }
I think devres_free() should now be called in one place, under the new 'err2' label.
WBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html