Changeset 33d19a7 in mainline for uspace/drv/ohci/hw_struct/transfer_descriptor.h

Timestamp:

2011-05-18T10:40:34Z (13 years ago)

Author:

Jan Vesely <jano.vesely@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

68b9f148

Parents:

c7b5826

Message:

Fix OHCI buffer access.

Consider more than one data transaction when computing transfered size.
Reduce max transfer size to 4KB to guarantee that max 2 pages will be used.

File:

• uspace/drv/ohci/hw_struct/transfer_descriptor.h (modified) (1 diff)

uspace/drv/ohci/hw_struct/transfer_descriptor.h

@@ -41 +41 @@
 #include "completion_codes.h"
 
-/* OHCI TDs can handle up to 8KB buffers */
-#define OHCI_TD_MAX_TRANSFER (8 * 1024)
+/* OHCI TDs can handle up to 8KB buffers, however, it can use max 2 pages.
+ * Using 4KB buffers guarantees the page count condition.
+ * (OHCI assumes 4KB pages) */
+#define OHCI_TD_MAX_TRANSFER (4 * 1024)
 
 typedef struct td {