From 72cc9ba39a046132a638888eaa5a14baf55621b2 Mon Sep 17 00:00:00 2001 From: Frank Schaefer Date: Wed, 27 Mar 2013 16:07:41 -0300 Subject: [PATCH] [media] em28xx: ignore isoc DVB USB endpoints with wMaxPacketSize = 0 bytes for all alt settings MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Some devices without DVB support (such as the "Terratec Grabby" and "Easycap DC-60") provide isochronous DVB USB endpoints with wMaxPacketSize set to 0 bytes for all alt settings. Ignore these endpoints and avoid registering a DVB device node and loading the DVB driver extension. Signed-off-by: Frank Schäfer Tested-by: Timo Teräs Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/em28xx/em28xx-cards.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c index 54e0362d8e3..09620633413 100644 --- a/drivers/media/usb/em28xx/em28xx-cards.c +++ b/drivers/media/usb/em28xx/em28xx-cards.c @@ -3357,14 +3357,15 @@ static int em28xx_usb_probe(struct usb_interface *interface, dev->analog_ep_bulk = e->bEndpointAddress; } else { - has_dvb = true; if (usb_endpoint_xfer_isoc(e)) { dev->dvb_ep_isoc = e->bEndpointAddress; if (size > dev->dvb_max_pkt_size_isoc) { + has_dvb = true; /* see NOTE (~) */ dev->dvb_max_pkt_size_isoc = size; dev->dvb_alt_isoc = i; } } else { + has_dvb = true; dev->dvb_ep_bulk = e->bEndpointAddress; } } @@ -3391,6 +3392,12 @@ static int em28xx_usb_probe(struct usb_interface *interface, * so far. But there might be devices for which this * logic is not sufficient... */ + /* + * NOTE (~): some manufacturers (e.g. Terratec) disable + * endpoints by setting wMaxPacketSize to 0 bytes for + * all alt settings. So far, we've seen this for + * DVB isoc endpoints only. + */ } } -- 2.46.0