Merge tag 'firewire-fix' of git://git.kernel.org/pub/scm/linux/kernel…

…/git/ieee1394/linux1394

Pull firewire regression fix from Stefan Richter:
 "This fixes corrupted video capture, seen with IIDC/DCAM video and
  certain buffer settings.  (Regression since v3.4 inclusive.)"

* tag 'firewire-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394:
  firewire: fix libdc1394/FlyCap2 iso event regression

drivers/firewire/core-cdev.c

@@ -54,6 +54,7 @@
 #define FW_CDEV_KERNEL_VERSION			5
 #define FW_CDEV_VERSION_EVENT_REQUEST2		4
 #define FW_CDEV_VERSION_ALLOCATE_REGION_END	4
+#define FW_CDEV_VERSION_AUTO_FLUSH_ISO_OVERFLOW	5
 
 struct client {
 	u32 version;
@@ -1005,6 +1006,8 @@ static int ioctl_create_iso_context(struct client *client, union ioctl_arg *arg)
 			a->channel, a->speed, a->header_size, cb, client);
 	if (IS_ERR(context))
 		return PTR_ERR(context);
+	if (client->version < FW_CDEV_VERSION_AUTO_FLUSH_ISO_OVERFLOW)
+		context->drop_overflow_headers = true;
 
 	/* We only support one context at this time. */
 	spin_lock_irq(&client->lock);

drivers/firewire/ohci.c

@@ -2749,8 +2749,11 @@ static void copy_iso_headers(struct iso_context *ctx, const u32 *dma_hdr)
 {
 	u32 *ctx_hdr;
 
-	if (ctx->header_length + ctx->base.header_size > PAGE_SIZE)
+	if (ctx->header_length + ctx->base.header_size > PAGE_SIZE) {
+		if (ctx->base.drop_overflow_headers)
+			return;
 		flush_iso_completions(ctx);
+	}
 
 	ctx_hdr = ctx->header + ctx->header_length;
 	ctx->last_timestamp = (u16)le32_to_cpu((__force __le32)dma_hdr[0]);
@@ -2910,8 +2913,11 @@ static int handle_it_packet(struct context *context,
 
 	sync_it_packet_for_cpu(context, d);
 
-	if (ctx->header_length + 4 > PAGE_SIZE)
+	if (ctx->header_length + 4 > PAGE_SIZE) {
+		if (ctx->base.drop_overflow_headers)
+			return 1;
 		flush_iso_completions(ctx);
+	}
 
 	ctx_hdr = ctx->header + ctx->header_length;
 	ctx->last_timestamp = le16_to_cpu(last->res_count);

include/linux/firewire.h

@@ -436,6 +436,7 @@ struct fw_iso_context {
 	int type;
 	int channel;
 	int speed;
+	bool drop_overflow_headers;
 	size_t header_size;
 	union {
 		fw_iso_callback_t sc;

include/uapi/linux/firewire-cdev.h

@@ -215,8 +215,8 @@ struct fw_cdev_event_request2 {
  * with the %FW_CDEV_ISO_INTERRUPT bit set, when explicitly requested with
  * %FW_CDEV_IOC_FLUSH_ISO, or when there have been so many completed packets
  * without the interrupt bit set that the kernel's internal buffer for @header
- * is about to overflow.  (In the last case, kernels with ABI version < 5 drop
- * header data up to the next interrupt packet.)
+ * is about to overflow.  (In the last case, ABI versions < 5 drop header data
+ * up to the next interrupt packet.)
  *
  * Isochronous transmit events (context type %FW_CDEV_ISO_CONTEXT_TRANSMIT):
  *