3 files changed, 58 insertions, 3 deletions

diff --git a/drivers/media/video/uvc/uvc_ctrl.c b/drivers/media/video/uvc/uvc_ctrl.c
index f16aafe9cf14..77b92e67953d 100644
--- a/drivers/media/video/uvc/uvc_ctrl.c
+++ b/drivers/media/video/uvc/uvc_ctrl.c
@@ -543,11 +543,16 @@ static inline __u8 *uvc_ctrl_data(struct uvc_control *ctrl, int id)
         return ctrl->data + id * ctrl->info->size;
 }
 
-static inline int uvc_get_bit(const __u8 *data, int bit)
+static inline int uvc_test_bit(const __u8 *data, int bit)
 {
         return (data[bit >> 3] >> (bit & 7)) & 1;
 }
 
+static inline void uvc_clear_bit(__u8 *data, int bit)
+{
+        data[bit >> 3] &= ~(1 << (bit & 7));
+}
+
 /* Extract the bit string specified by mapping->offset and mapping->size
  * from the little-endian data stored at 'data' and return the result as
  * a signed 32bit integer. Sign extension will be performed if the mapping
@@ -1306,6 +1311,51 @@ end:
 }
 
 /*
+ * Prune an entity of its bogus controls. This currently includes processing
+ * unit auto controls for which no corresponding manual control is available.
+ * Such auto controls make little sense if any, and are known to crash at
+ * least the SiGma Micro webcam.
+ */
+static void
+uvc_ctrl_prune_entity(struct uvc_entity *entity)
+{
+        static const struct {
+                u8 idx_manual;
+                u8 idx_auto;
+        } blacklist[] = {
+                { 2, 11 }, /* Hue */
+                { 6, 12 }, /* White Balance Temperature */
+                { 7, 13 }, /* White Balance Component */
+        };
+
+        u8 *controls;
+        unsigned int size;
+        unsigned int i;
+
+        if (UVC_ENTITY_TYPE(entity) != VC_PROCESSING_UNIT)
+                return;
+
+        controls = entity->processing.bmControls;
+        size = entity->processing.bControlSize;
+
+        for (i = 0; i < ARRAY_SIZE(blacklist); ++i) {
+                if (blacklist[i].idx_auto >= 8 * size ||
+                    blacklist[i].idx_manual >= 8 * size)
+                        continue;
+
+                if (!uvc_test_bit(controls, blacklist[i].idx_auto) ||
+                     uvc_test_bit(controls, blacklist[i].idx_manual))
+                        continue;
+
+                uvc_trace(UVC_TRACE_CONTROL, "Auto control %u/%u has no "
+                        "matching manual control, removing it.\n", entity->id,
+                        blacklist[i].idx_auto);
+
+                uvc_clear_bit(controls, blacklist[i].idx_auto);
+        }
+}
+
+/*
  * Initialize device controls.
  */
 int uvc_ctrl_init_device(struct uvc_device *dev)
@@ -1331,6 +1381,9 @@ int uvc_ctrl_init_device(struct uvc_device *dev)
                         bControlSize = entity->camera.bControlSize;
                 }
 
+                if (dev->quirks & UVC_QUIRK_PRUNE_CONTROLS)
+                        uvc_ctrl_prune_entity(entity);
+
                 for (i = 0; i < bControlSize; ++i)
                         ncontrols += hweight8(bmControls[i]);
 
@@ -1345,7 +1398,7 @@ int uvc_ctrl_init_device(struct uvc_device *dev)
 
                 ctrl = entity->controls;
                 for (i = 0; i < bControlSize * 8; ++i) {
-                        if (uvc_get_bit(bmControls, i) == 0)
+                        if (uvc_test_bit(bmControls, i) == 0)
                                 continue;
 
                         ctrl->entity = entity;
diff --git a/drivers/media/video/uvc/uvc_driver.c b/drivers/media/video/uvc/uvc_driver.c
index a67533f11f2e..1054c7656aef 100644
--- a/drivers/media/video/uvc/uvc_driver.c
+++ b/drivers/media/video/uvc/uvc_driver.c
@@ -1894,7 +1894,8 @@ static struct usb_device_id uvc_ids[] = {
           .bInterfaceSubClass   = 1,
           .bInterfaceProtocol   = 0,
           .driver_info          = UVC_QUIRK_PROBE_MINMAX
-                                | UVC_QUIRK_IGNORE_SELECTOR_UNIT},
+                                | UVC_QUIRK_IGNORE_SELECTOR_UNIT
+                                | UVC_QUIRK_PRUNE_CONTROLS },
         /* Generic USB Video Class */
         { USB_INTERFACE_INFO(USB_CLASS_VIDEO, 1, 0) },
         {}
diff --git a/drivers/media/video/uvc/uvcvideo.h b/drivers/media/video/uvc/uvcvideo.h
index 437df60e0dae..00d593776b86 100644
--- a/drivers/media/video/uvc/uvcvideo.h
+++ b/drivers/media/video/uvc/uvcvideo.h
@@ -316,6 +316,7 @@ struct uvc_xu_control {
 #define UVC_QUIRK_BUILTIN_ISIGHT        0x00000008
 #define UVC_QUIRK_STREAM_NO_FID         0x00000010
 #define UVC_QUIRK_IGNORE_SELECTOR_UNIT  0x00000020
+#define UVC_QUIRK_PRUNE_CONTROLS        0x00000040
 
 /* Format flags */
 #define UVC_FMT_FLAG_COMPRESSED         0x00000001