[Spice-devel] [PATCH spice-gtk 1/3] Suppress libusb open error messages when trying to open a device

[Hans de Goede]

Hi,

On 11/20/2011 11:58 PM, Marc-André Lureau wrote:
> hi
>
> On Sat, Nov 19, 2011 at 4:29 PM, Hans de Goede<hdegoede at redhat.com>  wrote:
>>     /* Silence open failing (ie permission denied) errors */
>> +    g_object_set(priv->context, "debug_level", 0, NULL);
>>      rc = libusb_open(_g_usb_device_get_device(priv->device),&handle);
>> +    g_object_set(priv->context, "debug_level",
>> +                 spice_util_get_debug() ? 3 : 2, NULL);
>
> You have to admit it looks more like a quick patch rather than a
> proper solution.

I admit :)

> It would make sense if it would report a GError domain/code when
> trying to open a device. This would need a wrap of libusb_open, which
> I wonder why it is not done yet

GUsb already has a class for this, but libusbredirhost does not
use gusb, it wants a raw libusb device handle. Note that I could
change the g_object_set(priv->context calls with raw libusb calls
to match, that wouldn't make the code prettier, but it would make
it more consistent. Also before you ask I use 0, 2 and 3 and not
defines, because libusb has no defines for these ...

> and perhaps some changes in libusb
> also, to not print a "normal error" case.

I'm afraid that libusb has 2 (well it has 4 levels) modes:
1) Silent in all cases
2) print errors in all error cases including once which could be
considered more or less normal.

I also think that some libusb programs will depend on libusb reporting
an error to the user in this case, and thus won't do that themselves...

Regards,

Hans