This is a note to let you know that I've just added the patch titled
uvcvideo: uvc_scan_fallback() for webcams with broken chain
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
uvcvideo-uvc_scan_fallback-for-webcams-with-broken-chain.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Mar 28 13:59:27 CEST 2017
From: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Date: Sat, 25 Mar 2017 21:48:16 +0530
Subject: uvcvideo: uvc_scan_fallback() for webcams with broken chain
To: stable@xxxxxxxxxxxxxxx
Cc: Henrik Ingo <henrik.ingo@xxxxxxxxxxxxx>, Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>, Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>, Sasha Levin <alexander.levin@xxxxxxxxxxx>, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Message-ID: <1490458699-24484-17-git-send-email-sumit.semwal@xxxxxxxxxx>
From: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
From: Henrik Ingo <henrik.ingo@xxxxxxxxxxxxx>
[ Upstream commit e950267ab802c8558f1100eafd4087fd039ad634 ]
Some devices have invalid baSourceID references, causing uvc_scan_chain()
to fail, but if we just take the entities we can find and put them
together in the most sensible chain we can think of, turns out they do
work anyway. Note: This heuristic assumes there is a single chain.
At the time of writing, devices known to have such a broken chain are
- Acer Integrated Camera (5986:055a)
- Realtek rtl157a7 (0bda:57a7)
Signed-off-by: Henrik Ingo <henrik.ingo@xxxxxxxxxxxxx>
Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/media/usb/uvc/uvc_driver.c | 118 +++++++++++++++++++++++++++++++++++--
1 file changed, 112 insertions(+), 6 deletions(-)
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -1595,6 +1595,114 @@ static const char *uvc_print_chain(struc
return buffer;
}
+static struct uvc_video_chain *uvc_alloc_chain(struct uvc_device *dev)
+{
+ struct uvc_video_chain *chain;
+
+ chain = kzalloc(sizeof(*chain), GFP_KERNEL);
+ if (chain == NULL)
+ return NULL;
+
+ INIT_LIST_HEAD(&chain->entities);
+ mutex_init(&chain->ctrl_mutex);
+ chain->dev = dev;
+ v4l2_prio_init(&chain->prio);
+
+ return chain;
+}
+
+/*
+ * Fallback heuristic for devices that don't connect units and terminals in a
+ * valid chain.
+ *
+ * Some devices have invalid baSourceID references, causing uvc_scan_chain()
+ * to fail, but if we just take the entities we can find and put them together
+ * in the most sensible chain we can think of, turns out they do work anyway.
+ * Note: This heuristic assumes there is a single chain.
+ *
+ * At the time of writing, devices known to have such a broken chain are
+ * - Acer Integrated Camera (5986:055a)
+ * - Realtek rtl157a7 (0bda:57a7)
+ */
+static int uvc_scan_fallback(struct uvc_device *dev)
+{
+ struct uvc_video_chain *chain;
+ struct uvc_entity *iterm = NULL;
+ struct uvc_entity *oterm = NULL;
+ struct uvc_entity *entity;
+ struct uvc_entity *prev;
+
+ /*
+ * Start by locating the input and output terminals. We only support
+ * devices with exactly one of each for now.
+ */
+ list_for_each_entry(entity, &dev->entities, list) {
+ if (UVC_ENTITY_IS_ITERM(entity)) {
+ if (iterm)
+ return -EINVAL;
+ iterm = entity;
+ }
+
+ if (UVC_ENTITY_IS_OTERM(entity)) {
+ if (oterm)
+ return -EINVAL;
+ oterm = entity;
+ }
+ }
+
+ if (iterm == NULL || oterm == NULL)
+ return -EINVAL;
+
+ /* Allocate the chain and fill it. */
+ chain = uvc_alloc_chain(dev);
+ if (chain == NULL)
+ return -ENOMEM;
+
+ if (uvc_scan_chain_entity(chain, oterm) < 0)
+ goto error;
+
+ prev = oterm;
+
+ /*
+ * Add all Processing and Extension Units with two pads. The order
+ * doesn't matter much, use reverse list traversal to connect units in
+ * UVC descriptor order as we build the chain from output to input. This
+ * leads to units appearing in the order meant by the manufacturer for
+ * the cameras known to require this heuristic.
+ */
+ list_for_each_entry_reverse(entity, &dev->entities, list) {
+ if (entity->type != UVC_VC_PROCESSING_UNIT &&
+ entity->type != UVC_VC_EXTENSION_UNIT)
+ continue;
+
+ if (entity->num_pads != 2)
+ continue;
+
+ if (uvc_scan_chain_entity(chain, entity) < 0)
+ goto error;
+
+ prev->baSourceID[0] = entity->id;
+ prev = entity;
+ }
+
+ if (uvc_scan_chain_entity(chain, iterm) < 0)
+ goto error;
+
+ prev->baSourceID[0] = iterm->id;
+
+ list_add_tail(&chain->list, &dev->chains);
+
+ uvc_trace(UVC_TRACE_PROBE,
+ "Found a video chain by fallback heuristic (%s).\n",
+ uvc_print_chain(chain));
+
+ return 0;
+
+error:
+ kfree(chain);
+ return -EINVAL;
+}
+
/*
* Scan the device for video chains and register video devices.
*
@@ -1617,15 +1725,10 @@ static int uvc_scan_device(struct uvc_de
if (term->chain.next || term->chain.prev)
continue;
- chain = kzalloc(sizeof(*chain), GFP_KERNEL);
+ chain = uvc_alloc_chain(dev);
if (chain == NULL)
return -ENOMEM;
- INIT_LIST_HEAD(&chain->entities);
- mutex_init(&chain->ctrl_mutex);
- chain->dev = dev;
- v4l2_prio_init(&chain->prio);
-
term->flags |= UVC_ENTITY_FLAG_DEFAULT;
if (uvc_scan_chain(chain, term) < 0) {
@@ -1639,6 +1742,9 @@ static int uvc_scan_device(struct uvc_de
list_add_tail(&chain->list, &dev->chains);
}
+ if (list_empty(&dev->chains))
+ uvc_scan_fallback(dev);
+
if (list_empty(&dev->chains)) {
uvc_printk(KERN_INFO, "No valid video chain found.\n");
return -1;
Patches currently in stable-queue which might be from sumit.semwal@xxxxxxxxxx are
queue-4.4/pci-add-comments-about-rom-bar-updating.patch
queue-4.4/acpi-blacklist-make-dell-latitude-3350-ethernet-work.patch
queue-4.4/s390-zcrypt-introduce-cex6-toleration.patch
queue-4.4/block-allow-write_same-commands-with-the-sg_io-ioctl.patch
queue-4.4/pci-do-any-vf-bar-updates-before-enabling-the-bars.patch
queue-4.4/x86-hyperv-handle-unknown-nmis-on-one-cpu-when-unknown_nmi_panic.patch
queue-4.4/serial-8250_pci-detach-low-level-driver-during-pci-error-recovery.patch
queue-4.4/xen-do-not-re-use-pirq-number-cached-in-pci-device-msi-msg-data.patch
queue-4.4/pci-separate-vf-bar-updates-from-standard-bar-updates.patch
queue-4.4/pci-ignore-bar-updates-on-virtual-functions.patch
queue-4.4/pci-update-bars-using-property-bits-appropriate-for-type.patch
queue-4.4/vfio-spapr-postpone-allocation-of-userspace-version-of-tce-table.patch
queue-4.4/pci-don-t-update-vf-bars-while-vf-memory-space-is-enabled.patch
queue-4.4/igb-workaround-for-igb-i210-firmware-issue.patch
queue-4.4/pci-remove-pci_resource_bar-and-pci_iov_resource_bar.patch
queue-4.4/pci-decouple-ioresource_rom_enable-and-pci_rom_address_enable.patch
queue-4.4/acpi-blacklist-add-_rev-quirks-for-dell-precision-5520-and-3520.patch
queue-4.4/igb-add-i211-to-i210-phy-workaround.patch
queue-4.4/uvcvideo-uvc_scan_fallback-for-webcams-with-broken-chain.patch