From 72cc9ba39a046132a638888eaa5a14baf55621b2 Mon Sep 17 00:00:00 2001
From: Frank Schaefer <fschaefer.oss@googlemail.com>
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
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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 <fschaefer.oss@googlemail.com>
Tested-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
---
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 54e0362d8e3db..0962063341343 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.
+ */
}
}
--
2.30.2