> /n/sources/plan9/sys/src/cmd/usb/lib/dev.c:228,233 - dev.c:233,245
> memset(buf, 0, Ddevlen);
> if((nr=usbcmd(d, type, Rgetdesc, Ddev<<8|0, 0, buf, nr)) < 0)
> return -1;
> + if(nr == 17){
> + print("%s: langid %.4ux\n", argv0, buf[3]<<8|buf[2]);
> + if((nr = usbcmd(d, type, Rgetdesc, Ddev<<8|0,
> buf[3]<<8|buf[2], buf, 18)) < 0)
> + return -1;
> + print("%s: nr = %d; buf[%d] = %.2ux\n", argv0, nr, nr,
> buf[nr]);
> + }
> +
>
> This is in function loaddevdesc which loads a device descriptor, not a
> string descriptor. The device descriptor doesn't have a language id
> in offset 2:3, it has bcdUSB and bDeviceClass in those fields. And
> the specification for the Rgetdesc command says "the wIndex field
> specifies the LanguageID for string descriptors or is reset to zero
> for other descriptors".
you're right. looks like sloppy junk copied in mindlessly.
it seems that asking for exactly 18 bytes is enough.
i wonder if this will work for all devices. it does work for all
the ones i've got.
/n/sources/plan9/sys/src/cmd/usb/lib/dev.c:218,224 - dev.c:223,229
int
loaddevdesc(Dev *d)
{
- uchar buf[Ddevlen+255];
+ uchar buf[Ddevlen];
int nr;
int type;
Ep *ep0;
/n/sources/plan9/sys/src/cmd/usb/lib/dev.c:226,245 - dev.c:231,241
type = Rd2h|Rstd|Rdev;
nr = sizeof(buf);
memset(buf, 0, Ddevlen);
- if((nr=usbcmd(d, type, Rgetdesc, Ddev<<8|0, 0, buf, nr)) < 0)
+ if((nr = usbcmd(d, type, Rgetdesc, Ddev<<8|0, 0, buf, Ddevlen)) < 0)
return -1;
- /*
- * Several hubs are returning descriptors of 17 bytes, not 18.
- * We accept them and leave number of configurations as zero.
- * (a get configuration descriptor also fails for them!)
- */
if(nr < Ddevlen){
- print("%s: %s: warning: device with short descriptor\n",
- argv0, d->dir);
- if(nr < Ddevlen-1){
- werrstr("short device descriptor (%d bytes)", nr);
- return -1;
- }
+ werrstr("short device descriptor (%d bytes)", nr);
+ return -1;
}
d->usb = emallocz(sizeof(Usbdev), 1);
ep0 = mkep(d->usb, 0);
interestingly, on the pc i plugged the imac keyboard into,
usb/kb hung. this is the kernel stack even *after* pulling
the keyboard.
acid; stk()
sleep(r=0xf0daba30,arg=0xf0d55680,f=0xf013fc71)+0x16a
/sys/src/nix/port/proc.c:928
epiowait(io=0xf0dab9e0,hp=0xf0d4d6b0,tmout=0x0,load=0x11)+0x37e
/sys/src/nix/port/usbehci.c:2289
epio(io=0xf0dab9e0,ep=0xf0dab720,count=0x8,a=0x442917,mustlock=0x1)+0x38e
/sys/src/nix/port/usbehci.c:2423
epread(ep=0xf0dab720,count=0x8,a=0x442917)+0x16f
/sys/src/nix/port/usbehci.c:2534
usbread(c=0xf0dab840,a=0x442917,n=0x8,offset=0x0)+0x17d
/sys/src/nix/port/devusb.c:1070
read(list=0xf056be24,ispread=0x0)+0x269 /sys/src/nix/port/sysfile.c:745
syspread(ar0=0xf0dafa90,list=0xf056be04)+0x1c /sys/src/nix/port/sysfile.c:766
syscall(scallnr=0x32,ureg=0xf0dafad8)+0x22e /sys/src/nix/k10/syscall.c:273
syscallreturn()+0x0 /sys/src/nix/k10/l64syscall.s:52
- erik
