|
 |
c8dfc6 |
From d2901e4798cb106d5b265aa4e3ae05c06bf2bd1c Mon Sep 17 00:00:00 2001
|
|
|
c8dfc6 |
From: Hans de Goede <hdegoede@redhat.com>
|
|
|
c8dfc6 |
Date: Thu, 6 Sep 2012 17:10:48 +0200
|
|
|
c8dfc6 |
Subject: [PATCH 360/366] ehci: Don't process too much frames in 1 timer tick
|
|
|
c8dfc6 |
|
|
|
c8dfc6 |
The Linux ehci isoc scheduling code fills the entire schedule ahead of
|
|
|
c8dfc6 |
time minus 80 frames. If we make a large jump in where we are in the
|
|
|
c8dfc6 |
schedule, ie 40 frames, then the scheduler all of a sudden will only have
|
|
|
c8dfc6 |
40 frames left to work in, causing it to fail packet submissions
|
|
|
c8dfc6 |
with error -27 (-EFBIG).
|
|
|
c8dfc6 |
|
|
|
c8dfc6 |
Note at first I had MAX_FR_PER_TICK set to 8, which works well with newer
|
|
|
c8dfc6 |
Linux guest kernels, but not with older ones (such as the RHEL-6 kernel).
|
|
|
c8dfc6 |
|
|
|
c8dfc6 |
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
|
|
|
c8dfc6 |
---
|
|
|
c8dfc6 |
hw/usb/hcd-ehci.c | 9 +++++++++
|
|
|
c8dfc6 |
1 file changed, 9 insertions(+)
|
|
|
c8dfc6 |
|
|
|
c8dfc6 |
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
|
|
|
c8dfc6 |
index 30d2b56..5398544 100644
|
|
|
c8dfc6 |
--- a/hw/usb/hcd-ehci.c
|
|
|
c8dfc6 |
+++ b/hw/usb/hcd-ehci.c
|
|
|
c8dfc6 |
@@ -140,6 +140,7 @@
|
|
|
c8dfc6 |
#define NB_PORTS 6 // Number of downstream ports
|
|
|
c8dfc6 |
#define BUFF_SIZE 5*4096 // Max bytes to transfer per transaction
|
|
|
c8dfc6 |
#define MAX_QH 100 // Max allowable queue heads in a chain
|
|
|
c8dfc6 |
+#define MAX_FR_PER_TICK 4 /* Max frames to process in one timer tick */
|
|
|
c8dfc6 |
|
|
|
c8dfc6 |
/* Internal periodic / asynchronous schedule state machine states
|
|
|
c8dfc6 |
*/
|
|
|
c8dfc6 |
@@ -2460,6 +2461,14 @@ static void ehci_frame_timer(void *opaque)
|
|
|
c8dfc6 |
DPRINTF("WARNING - EHCI skipped %d frames\n", skipped_frames);
|
|
|
c8dfc6 |
}
|
|
|
c8dfc6 |
|
|
|
c8dfc6 |
+ /*
|
|
|
c8dfc6 |
+ * Processing too much frames at once causes the Linux EHCI isoc
|
|
|
c8dfc6 |
+ * scheduling code to fail packet re-submissions with -EFBIG.
|
|
|
c8dfc6 |
+ */
|
|
|
c8dfc6 |
+ if (frames > MAX_FR_PER_TICK) {
|
|
|
c8dfc6 |
+ frames = MAX_FR_PER_TICK;
|
|
|
c8dfc6 |
+ }
|
|
|
c8dfc6 |
+
|
|
|
c8dfc6 |
for (i = 0; i < frames; i++) {
|
|
|
c8dfc6 |
ehci_update_frindex(ehci, 1);
|
|
|
c8dfc6 |
ehci_advance_periodic_state(ehci);
|
|
|
c8dfc6 |
--
|
|
|
c8dfc6 |
1.7.12
|
|
|
c8dfc6 |
|