| Message ID | Pine.LNX.4.44L0.1609161017070.1657-100000@iolanthe.rowland.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Em Fri, 16 Sep 2016 10:24:26 -0400 (EDT) Alan Stern <stern@rowland.harvard.edu> escreveu: > Some full-speed mceusb infrared transceivers contain invalid endpoint > descriptors for their interrupt endpoints, with bInterval set to 0. > In the past they have worked out okay with the mceusb driver, because > the driver sets the bInterval field in the descriptor to 1, > overwriting whatever value may have been there before. However, this > approach was never sanctioned by the USB core, and in fact it does not > work with xHCI controllers, because they use the bInterval value that > was present when the configuration was installed. > > Currently usbcore uses 32 ms as the default interval if the value in > the endpoint descriptor is invalid. It turns out that these IR > transceivers don't work properly unless the interval is set to 10 ms > or below. To work around this mceusb problem, this patch changes the > endpoint-descriptor parsing routine, making the default interval value > be 10 ms rather than 32 ms. > > Signed-off-by: Alan Stern <stern@rowland.harvard.edu> > Tested-by: Wade Berrier <wberrier@gmail.com> > CC: <stable@vger.kernel.org> Acked-by: Mauro Carvalho Chehab <m.chehab@s-opensource.com> > > --- > > > [as1812] > > > drivers/usb/core/config.c | 28 +++++++++++++++++----------- > 1 file changed, 17 insertions(+), 11 deletions(-) > > Index: usb-4.x/drivers/usb/core/config.c > =================================================================== > --- usb-4.x.orig/drivers/usb/core/config.c > +++ usb-4.x/drivers/usb/core/config.c > @@ -240,8 +240,10 @@ static int usb_parse_endpoint(struct dev > memcpy(&endpoint->desc, d, n); > INIT_LIST_HEAD(&endpoint->urb_list); > > - /* Fix up bInterval values outside the legal range. Use 32 ms if no > - * proper value can be guessed. */ > + /* > + * Fix up bInterval values outside the legal range. > + * Use 10 or 8 ms if no proper value can be guessed. > + */ > i = 0; /* i = min, j = max, n = default */ > j = 255; > if (usb_endpoint_xfer_int(d)) { > @@ -250,13 +252,15 @@ static int usb_parse_endpoint(struct dev > case USB_SPEED_SUPER_PLUS: > case USB_SPEED_SUPER: > case USB_SPEED_HIGH: > - /* Many device manufacturers are using full-speed > + /* > + * Many device manufacturers are using full-speed > * bInterval values in high-speed interrupt endpoint > - * descriptors. Try to fix those and fall back to a > - * 32 ms default value otherwise. */ > + * descriptors. Try to fix those and fall back to an > + * 8-ms default value otherwise. > + */ > n = fls(d->bInterval*8); > if (n == 0) > - n = 9; /* 32 ms = 2^(9-1) uframes */ > + n = 7; /* 8 ms = 2^(7-1) uframes */ > j = 16; > > /* > @@ -271,10 +275,12 @@ static int usb_parse_endpoint(struct dev > } > break; > default: /* USB_SPEED_FULL or _LOW */ > - /* For low-speed, 10 ms is the official minimum. > + /* > + * For low-speed, 10 ms is the official minimum. > * But some "overclocked" devices might want faster > - * polling so we'll allow it. */ > - n = 32; > + * polling so we'll allow it. > + */ > + n = 10; > break; > } > } else if (usb_endpoint_xfer_isoc(d)) { > @@ -282,10 +288,10 @@ static int usb_parse_endpoint(struct dev > j = 16; > switch (to_usb_device(ddev)->speed) { > case USB_SPEED_HIGH: > - n = 9; /* 32 ms = 2^(9-1) uframes */ > + n = 7; /* 8 ms = 2^(7-1) uframes */ > break; > default: /* USB_SPEED_FULL */ > - n = 6; /* 32 ms = 2^(6-1) frames */ > + n = 4; /* 8 ms = 2^(4-1) frames */ > break; > } > } > Thanks, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Index: usb-4.x/drivers/usb/core/config.c =================================================================== --- usb-4.x.orig/drivers/usb/core/config.c +++ usb-4.x/drivers/usb/core/config.c @@ -240,8 +240,10 @@ static int usb_parse_endpoint(struct dev memcpy(&endpoint->desc, d, n); INIT_LIST_HEAD(&endpoint->urb_list); - /* Fix up bInterval values outside the legal range. Use 32 ms if no - * proper value can be guessed. */ + /* + * Fix up bInterval values outside the legal range. + * Use 10 or 8 ms if no proper value can be guessed. + */ i = 0; /* i = min, j = max, n = default */ j = 255; if (usb_endpoint_xfer_int(d)) { @@ -250,13 +252,15 @@ static int usb_parse_endpoint(struct dev case USB_SPEED_SUPER_PLUS: case USB_SPEED_SUPER: case USB_SPEED_HIGH: - /* Many device manufacturers are using full-speed + /* + * Many device manufacturers are using full-speed * bInterval values in high-speed interrupt endpoint - * descriptors. Try to fix those and fall back to a - * 32 ms default value otherwise. */ + * descriptors. Try to fix those and fall back to an + * 8-ms default value otherwise. + */ n = fls(d->bInterval*8); if (n == 0) - n = 9; /* 32 ms = 2^(9-1) uframes */ + n = 7; /* 8 ms = 2^(7-1) uframes */ j = 16; /* @@ -271,10 +275,12 @@ static int usb_parse_endpoint(struct dev } break; default: /* USB_SPEED_FULL or _LOW */ - /* For low-speed, 10 ms is the official minimum. + /* + * For low-speed, 10 ms is the official minimum. * But some "overclocked" devices might want faster - * polling so we'll allow it. */ - n = 32; + * polling so we'll allow it. + */ + n = 10; break; } } else if (usb_endpoint_xfer_isoc(d)) { @@ -282,10 +288,10 @@ static int usb_parse_endpoint(struct dev j = 16; switch (to_usb_device(ddev)->speed) { case USB_SPEED_HIGH: - n = 9; /* 32 ms = 2^(9-1) uframes */ + n = 7; /* 8 ms = 2^(7-1) uframes */ break; default: /* USB_SPEED_FULL */ - n = 6; /* 32 ms = 2^(6-1) frames */ + n = 4; /* 8 ms = 2^(4-1) frames */ break; } }