From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Mon, 30 Mar 2015 01:47:57 +0200 Subject: [U-Boot] [PATCH] usb: Early failure when the first descriptor read fails, one way or another In-Reply-To: <1427563902.8267.12.camel@collins> References: <1427563438-25427-1-git-send-email-contact@paulk.fr> <201503281826.20603.marex@denx.de> <1427563902.8267.12.camel@collins> Message-ID: <201503300147.57183.marex@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Saturday, March 28, 2015 at 06:31:42 PM, Paul Kocialkowski wrote: > Le samedi 28 mars 2015 ? 18:26 +0100, Marek Vasut a ?crit : > > On Saturday, March 28, 2015 at 06:23:58 PM, Paul Kocialkowski wrote: > > > When using an USB1 device on a controller that only supports USB2 (e.g. > > > EHCI), reading the first descriptor will fail (read 0 byte), so we can > > > abort the process at this point instead of failing later and wasting > > > time. > > > > > > Signed-off-by: Paul Kocialkowski > > > --- > > > > > > common/usb.c | 5 ++++- > > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > > > diff --git a/common/usb.c b/common/usb.c > > > index 32e15cd..d1b3316 100644 > > > --- a/common/usb.c > > > +++ b/common/usb.c > > > @@ -950,7 +950,7 @@ int usb_new_device(struct usb_device *dev) > > > > > > */ > > > > > > #ifndef CONFIG_USB_XHCI > > > > > > err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, 64); > > > > > > - if (err < 0) { > > > + if (err < sizeof(struct usb_device_descriptor)) { > > > > > > debug("usb_new_device: usb_get_descriptor() failed\n"); > > > return 1; > > > > > > } > > > > > > @@ -990,6 +990,9 @@ int usb_new_device(struct usb_device *dev) > > > > > > case 64: > > > dev->maxpacketsize = PACKET_SIZE_64; > > > break; > > > > > > + default: > > > + debug("usb_new_device: invalid max packet size\n"); > > > > Hi, > > > > since this is an error, this should probably be a printf(). Also, > > to make the error message useful, it should state the invalid value > > due to which it failed. > > Well, it is not unexpected behaviour in my use case (but I reckon it may > be generally speaking). Why is this not unexpected in your case please ? > Plugging an USB1 device on a controller that > doesn't support USB1 should normally fail, this is not some kind of > run-time error. Yes. > When this happens in Linux, it just fails (silently) and tries ohci > instead. I'm afraid there is no such mechanism in U-Boot, so the best we > can do is to treat the device as unsupported. There's no such mechanism indeed. It'd be nice if someone implemented this handover though. > If you're not convinced by this, I can still make a v2 with printf, I > just don't think it's a necessity. Let me just understand what you're seeing a bit better first please . Best regards,