uhci: Increase bulk transfer STACKTDS to 16

Increase the number of simultaneous transfer descriptors that the
driver will build for uhci.  The old value of 4 was a leftover from
when SeaBIOS had a tiny 512 byte extra stack - now that there is a 2K
extra stack there is plenty of space for additional descriptors.
Using a value of 16 should allow for an entire 1ms frame of bulk
transfer content to be setup in advance (assuming the max packet size
is 64 bytes).

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

diff --git a/src/hw/usb-uhci.c b/src/hw/usb-uhci.c
index 7ef50d118c912ecf3817fc07844e9a93cc665bff..06a1d4e1771b9ae2e320f7a2d4d440b4403f8657 100644 (file)
--- a/src/hw/usb-uhci.c
+++ b/src/hw/usb-uhci.c
@@ -500,7 +500,7 @@ uhci_send_control(struct usb_pipe *p, int dir, const void *cmd, int cmdsize
     return ret;
 }
 
-#define STACKTDS 4
+#define STACKTDS 16
 #define TDALIGN 16
 
 int
@@ -517,7 +517,7 @@ uhci_send_bulk(struct usb_pipe *p, int dir, void *data, int datasize)
                    | (GET_LOWFLAT(pipe->pipe.ep) << 7));
     int toggle = GET_LOWFLAT(pipe->toggle) ? TD_TOKEN_TOGGLE : 0;
 
-    // Allocate 4 tds on stack (16byte aligned)
+    // Allocate 16 tds on stack (16byte aligned)
     u8 tdsbuf[sizeof(struct uhci_td) * STACKTDS + TDALIGN - 1];
     struct uhci_td *tds = (void*)ALIGN((u32)tdsbuf, TDALIGN);
     memset(tds, 0, sizeof(*tds) * STACKTDS);