On Tue, 3 Jul 2012, Lan Tianyu wrote:
> hi alan:
> I have done some experiments. I insert clear PORT_POWER in the
> hub_port_connect_change()
> to simulate such situation. I found there is leak if I clear PORT_POWER in the
> hub_port_connect_change()
> after hub_port_init() and before usb_new_device().
>
> [ 7.083502] xhci_hub_control: clear port power, actual port 1 status = 0xe01
> [ 7.090793] usb 1-2: unable to read config index 0 descriptor/start: -71
> [ 7.097469] usb 1-2: chopping to 0 config(s)
> [ 7.098898] ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
> [ 7.107898] ata2.00: ATAPI: Optiarc BD ROM BC-5640H, 1.00, max UDMA/100
> [ 7.107982] usb 1-2: string descriptor 0 read error: -71
> [ 7.107988] usb 1-2: New USB device found, idVendor=0781, idProduct=5567
> [ 7.107990] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
> [ 7.108144] usb 1-2: no configuration chosen from 0 choices
> In usb_get_configuration(), usb_get_descriptor failed but not return err. The
> device
> was still enumerated. I do following change and it works. Why here don't return err?
I don't remember the reason. It may be that some devices are broken
and don't just don't send some of their config descriptors correctly.
> diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
> index f4bdd0c..90f962b 100644
> --- a/drivers/usb/core/config.c
> +++ b/drivers/usb/core/config.c
> @@ -704,7 +704,7 @@ int usb_get_configuration(struct usb_device *dev)
> "descriptor/%s: %d\n", cfgno, "start", result);
> dev_err(ddev, "chopping to %d config(s)\n", cfgno);
> dev->descriptor.bNumConfigurations = cfgno;
> - break;
> + goto err;
> } else if (result < 4) {
> dev_err(ddev, "config index %d descriptor too short "
> "(expected %i, got %i)\n", cfgno,
Perhaps it would be best to do:
dev_err(ddev, "chopping to %d config(s)\n", cfgno);
dev->descriptor.bNumConfigurations = cfgno;
+ if (result != -EPIPE)
+ goto err;
break;
} else if (result < 4) {
dev_err(ddev, "config index %d descriptor too short "
Alan Stern
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