firewire: fix libdc1394/FlyCap2 iso event regression

Commit 18d627113b83 (firewire: prevent dropping of completed iso packet
header data) was intended to be an obvious bug fix, but libdc1394 and
FlyCap2 depend on the old behaviour by ignoring all returned information
and thus not noticing that not all packets have been received yet.  The
result was that the video frame buffers would be saved before they
contained the correct data.

Reintroduce the old behaviour for old clients.

Tested-by: Stepan Salenikovich <stepan.salenikovich@gmail.com>
Tested-by: Josep Bosch <jep250@gmail.com>
Cc: <stable@vger.kernel.org> # 3.4+
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 7ef316fdc4d964cc8d1f87bd7be0cb9995223612..ac1b43a0428531273c4fdaefd56a0b83f1545ce2 100644 (file)
--- a/drivers/firewire/core-cdev.c
+++ b/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);

diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 9e1db6490b9a3bb497b7911d94c42d9fc6190be7..afb701ec90cabd50ceb03b1298beba38e97717b4 100644 (file)
--- a/drivers/firewire/ohci.c
+++ b/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);

diff --git a/include/linux/firewire.h b/include/linux/firewire.h
index 3b0e820375ab90c2e0f9a05ffaa94f7a36f76abd..5d7782e42b8f22f81df12652348ff9a21aebc7e4 100644 (file)
--- a/include/linux/firewire.h
+++ b/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;

diff --git a/include/uapi/linux/firewire-cdev.h b/include/uapi/linux/firewire-cdev.h
index d500369534972c2dede7208ba69d7815e389f299..1db453e4b550ebc84b10ca27f32dd4fdc2ecffd7 100644 (file)
--- a/include/uapi/linux/firewire-cdev.h
+++ b/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):
  *