-------- Original Message -------- Subject: Re: Problem: hiddev stops sending events after some error recoveries Date: Thu, 31 Jan 2008 14:55:16 -0200 From: Salvador Eduardo Tropea <[EMAIL PROTECTED]> To: Alan Stern <[EMAIL PROTECTED]> References: <[EMAIL PROTECTED]>
On 31/01/08 14:50, Alan Stern wrote: > On Thu, 31 Jan 2008, Salvador Eduardo Tropea wrote: > > >> On 30/01/08 14:05, Alan Stern wrote: >> >>> It's a bug for Set-Interface to fail. >>> >> Yes and not. >> >> >>> Following a reset, the device has no reason to fail such a request. >>> >>> >> The device doesn't, but you can lose a packet (i.e. CRC error). >> > > That's why the reset code includes several retries. > I see only one logged in syslog. Jan 29 11:51:51 kotori kernel: usb 3-2: reset low speed USB device using uhci_hcd and address 105 Jan 29 11:51:52 kotori kernel: usb 3-2: failed to restore interface 0 altsetting 0 (error=-71) Jan 29 11:51:52 kotori kernel: usb 3-2: USB disconnect, address 105 Jan 29 11:51:52 kotori kernel: usb 3-2: new low speed USB device using uhci_hcd and address 106 Jan 29 11:51:52 kotori kernel: usb 3-2: configuration #1 chosen from 1 choice >> In this >> case the kernel should properly recover. In this case the kernel is >> recovering, but the hiddev becomes useless because the device changed >> its address. I think the kernel should make this device invalid and >> inform a read error as soon as the user space tries to read from it. I >> think the application gets notified only if reading in blocking mode. >> > > >> It currently informs an error if the device is unplugged. IMHO that's >> the right thing to do, the user space application can then close the >> file handle and try to open it again, if it fails the application can >> then try to interact with the user asking to replug the device. >> > > When a reset fails, the kernel should do exactly the same thing as if > the device was unplugged. Are you saying that it doesn't? > Nope. My user space program continues reading from the hiddev device, of course it never gets events ;-) Important: I'm polling using a NONBLOCKing file handler. Regards, SET -- _______________________________________________________________ Ing. Salvador Eduardo Tropea http://utic.inti.gov.ar/ INTI-Electrónica e Informática Tel: (+54 11) 4724 6315 Colectora de Av. General Paz 5445 San Martín - B1650KNA Casilla de Correo 157 FAX: (+54 11) 4754 5194 Buenos Aires * Argentina http://www.inti.gov.ar/ - To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
