[PATCH v3 0/2] USB: EHCI: Allow users to override 80% max periodic bandwidth

[PATCH v3 0/2] USB: EHCI: Allow users to override 80% max periodic bandwidth

[Kirill Smelkov]

There are cases, when 80% max isochronous bandwidth is too limiting.

Let's allow knowledgeable users to override that 80% max limit explicitly for
extreme cases, like 2 high bandwidth isochronously streaming devices on the
same High Speed USB bus in order to make them work simultaneously.

See full details in PATCH 2/2.


Changes since v2:

 - changed the copyright in ehci-sysfs from David Brownell to Alan Stern;

 - added ACK to PATCH 1/2 from Alan Stern;

 - inspired by concerns raised by Sarah Sharp, added more details about testing
   done on N10 chipset, system stability, and that no-harm-is-done for those,
   who do not change uframe_periodic_max from default 100us;

 - when decreasing uframe_periodic_max, compare with the maximum number of
   microseconds already allocated for any uframe, instead of stopping as soon
   as it finds something above the new limit.


Changes since v1:

 - dropped RFC status as "this seems like the sort of feature somebody might
   reasonably want to use -- if they know exactly what they're doing";

 - new preparatory patch (1/2) which moves already-in-there sysfs code into
   ehci-sysfs.c;

 - moved uframe_periodic_max parameter from module option to sysfs attribute,
   so that it can be set per controller and at runtime, added validity checks;

 - clarified a bit bandwidth analysis for 96% max periodic setup as noticed by
   Alan Stern;

 - clarified patch description saying that set in stone 80% max periodic is
   specified by USB 2.0;


Kirill Smelkov (2):
  USB: EHCI: Move sysfs related bits into ehci-sysfs.c
  USB: EHCI: Allow users to override 80% max periodic bandwidth

 drivers/usb/host/ehci-hcd.c   |   11 ++-
 drivers/usb/host/ehci-hub.c   |   75 ----------------
 drivers/usb/host/ehci-sched.c |   17 ++--
 drivers/usb/host/ehci-sysfs.c |  190 +++++++++++++++++++++++++++++++++++++++++
 drivers/usb/host/ehci.h       |    2 +
 5 files changed, 208 insertions(+), 87 deletions(-)
 create mode 100644 drivers/usb/host/ehci-sysfs.c

-- 
1.7.6.rc3

[PATCH v3 1/2] USB: EHCI: Move sysfs related bits into ehci-sysfs.c

[Kirill Smelkov]

The only sysfs attr implemented so far is "companion" from ehci-hub.c,
but in the next patch we are going to add another sysfs file, so prior
to that let's structure things and move already-in-there sysfs code to
separate file.

NOTE: All the code I'm moving into this new file was written by Alan
Stern (in 57e06c11 "EHCI: force high-speed devices to run at full
speed"; Jan 16 2007), that's why I'm putting

    Copyright (C) 2007 by Alan Stern

there after explicit request from the author.

Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Acked-off-by: Alan Stern <stern@rowland.harvard.edu>
---
 drivers/usb/host/ehci-hcd.c   |    5 +-
 drivers/usb/host/ehci-hub.c   |   75 --------------------------------
 drivers/usb/host/ehci-sysfs.c |   94 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 97 insertions(+), 77 deletions(-)
 create mode 100644 drivers/usb/host/ehci-sysfs.c

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index e18862c..8306155 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -336,6 +336,7 @@ static void ehci_work(struct ehci_hcd *ehci);
 #include "ehci-mem.c"
 #include "ehci-q.c"
 #include "ehci-sched.c"
+#include "ehci-sysfs.c"
 
 /*-------------------------------------------------------------------------*/
 
@@ -520,7 +521,7 @@ static void ehci_stop (struct usb_hcd *hcd)
 	ehci_reset (ehci);
 	spin_unlock_irq(&ehci->lock);
 
-	remove_companion_file(ehci);
+	remove_sysfs_files(ehci);
 	remove_debug_files (ehci);
 
 	/* root hub is shut down separately (first, when possible) */
@@ -754,7 +755,7 @@ static int ehci_run (struct usb_hcd *hcd)
 	 * since the class device isn't created that early.
 	 */
 	create_debug_files(ehci);
-	create_companion_file(ehci);
+	create_sysfs_files(ehci);
 
 	return 0;
 }
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index ea6184b..d9e8d71 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -471,29 +471,6 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
 
 /*-------------------------------------------------------------------------*/
 
-/* Display the ports dedicated to the companion controller */
-static ssize_t show_companion(struct device *dev,
-			      struct device_attribute *attr,
-			      char *buf)
-{
-	struct ehci_hcd		*ehci;
-	int			nports, index, n;
-	int			count = PAGE_SIZE;
-	char			*ptr = buf;
-
-	ehci = hcd_to_ehci(bus_to_hcd(dev_get_drvdata(dev)));
-	nports = HCS_N_PORTS(ehci->hcs_params);
-
-	for (index = 0; index < nports; ++index) {
-		if (test_bit(index, &ehci->companion_ports)) {
-			n = scnprintf(ptr, count, "%d\n", index + 1);
-			ptr += n;
-			count -= n;
-		}
-	}
-	return ptr - buf;
-}
-
 /*
  * Sets the owner of a port
  */
@@ -528,58 +505,6 @@ static void set_owner(struct ehci_hcd *ehci, int portnum, int new_owner)
 	}
 }
 
-/*
- * Dedicate or undedicate a port to the companion controller.
- * Syntax is "[-]portnum", where a leading '-' sign means
- * return control of the port to the EHCI controller.
- */
-static ssize_t store_companion(struct device *dev,
-			       struct device_attribute *attr,
-			       const char *buf, size_t count)
-{
-	struct ehci_hcd		*ehci;
-	int			portnum, new_owner;
-
-	ehci = hcd_to_ehci(bus_to_hcd(dev_get_drvdata(dev)));
-	new_owner = PORT_OWNER;		/* Owned by companion */
-	if (sscanf(buf, "%d", &portnum) != 1)
-		return -EINVAL;
-	if (portnum < 0) {
-		portnum = - portnum;
-		new_owner = 0;		/* Owned by EHCI */
-	}
-	if (portnum <= 0 || portnum > HCS_N_PORTS(ehci->hcs_params))
-		return -ENOENT;
-	portnum--;
-	if (new_owner)
-		set_bit(portnum, &ehci->companion_ports);
-	else
-		clear_bit(portnum, &ehci->companion_ports);
-	set_owner(ehci, portnum, new_owner);
-	return count;
-}
-static DEVICE_ATTR(companion, 0644, show_companion, store_companion);
-
-static inline int create_companion_file(struct ehci_hcd *ehci)
-{
-	int	i = 0;
-
-	/* with integrated TT there is no companion! */
-	if (!ehci_is_TDI(ehci))
-		i = device_create_file(ehci_to_hcd(ehci)->self.controller,
-				       &dev_attr_companion);
-	return i;
-}
-
-static inline void remove_companion_file(struct ehci_hcd *ehci)
-{
-	/* with integrated TT there is no companion! */
-	if (!ehci_is_TDI(ehci))
-		device_remove_file(ehci_to_hcd(ehci)->self.controller,
-				   &dev_attr_companion);
-}
-
-
 /*-------------------------------------------------------------------------*/
 
 static int check_reset_complete (
diff --git a/drivers/usb/host/ehci-sysfs.c b/drivers/usb/host/ehci-sysfs.c
new file mode 100644
index 0000000..29824a9
--- /dev/null
+++ b/drivers/usb/host/ehci-sysfs.c
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2007 by Alan Stern
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/* this file is part of ehci-hcd.c */
+
+
+/* Display the ports dedicated to the companion controller */
+static ssize_t show_companion(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	struct ehci_hcd		*ehci;
+	int			nports, index, n;
+	int			count = PAGE_SIZE;
+	char			*ptr = buf;
+
+	ehci = hcd_to_ehci(bus_to_hcd(dev_get_drvdata(dev)));
+	nports = HCS_N_PORTS(ehci->hcs_params);
+
+	for (index = 0; index < nports; ++index) {
+		if (test_bit(index, &ehci->companion_ports)) {
+			n = scnprintf(ptr, count, "%d\n", index + 1);
+			ptr += n;
+			count -= n;
+		}
+	}
+	return ptr - buf;
+}
+
+/*
+ * Dedicate or undedicate a port to the companion controller.
+ * Syntax is "[-]portnum", where a leading '-' sign means
+ * return control of the port to the EHCI controller.
+ */
+static ssize_t store_companion(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct ehci_hcd		*ehci;
+	int			portnum, new_owner;
+
+	ehci = hcd_to_ehci(bus_to_hcd(dev_get_drvdata(dev)));
+	new_owner = PORT_OWNER;		/* Owned by companion */
+	if (sscanf(buf, "%d", &portnum) != 1)
+		return -EINVAL;
+	if (portnum < 0) {
+		portnum = - portnum;
+		new_owner = 0;		/* Owned by EHCI */
+	}
+	if (portnum <= 0 || portnum > HCS_N_PORTS(ehci->hcs_params))
+		return -ENOENT;
+	portnum--;
+	if (new_owner)
+		set_bit(portnum, &ehci->companion_ports);
+	else
+		clear_bit(portnum, &ehci->companion_ports);
+	set_owner(ehci, portnum, new_owner);
+	return count;
+}
+static DEVICE_ATTR(companion, 0644, show_companion, store_companion);
+
+static inline int create_sysfs_files(struct ehci_hcd *ehci)
+{
+	int	i = 0;
+
+	/* with integrated TT there is no companion! */
+	if (!ehci_is_TDI(ehci))
+		i = device_create_file(ehci_to_hcd(ehci)->self.controller,
+				       &dev_attr_companion);
+	return i;
+}
+
+static inline void remove_sysfs_files(struct ehci_hcd *ehci)
+{
+	/* with integrated TT there is no companion! */
+	if (!ehci_is_TDI(ehci))
+		device_remove_file(ehci_to_hcd(ehci)->self.controller,
+				   &dev_attr_companion);
+}
-- 
1.7.6.rc3

[PATCH v3 2/2] USB: EHCI: Allow users to override 80% max periodic bandwidth

[Kirill Smelkov]

There are cases, when 80% max isochronous bandwidth is too limiting.

For example I have two USB video capture cards which stream uncompressed
video, and to stream full NTSC + PAL videos we'd need

    NTSC 640x480 YUV422 @30fps      ~17.6 MB/s
    PAL  720x576 YUV422 @25fps      ~19.7 MB/s

isoc bandwidth.

Now, due to limited alt settings in capture devices NTSC one ends up
streaming with max_pkt_size=2688  and  PAL with max_pkt_size=2892, both
with interval=1. In terms of microframe time allocation this gives

    NTSC    ~53us
    PAL     ~57us

and together

    ~110us  >  100us == 80% of 125us uframe time.

So those two devices can't work together simultaneously because the'd
over allocate isochronous bandwidth.

80% seemed a bit arbitrary to me, and I've tried to raise it to 90% and
both devices started to work together, so I though sometimes it would be
a good idea for users to override hardcoded default of max 80% isoc
bandwidth.

After all, isn't it a user who should decide how to load the bus? If I
can live with 10% or even 5% bulk bandwidth that should be ok. I'm a USB
newcomer, but that 80% set in stone by USB 2.0 specification seems to be
chosen pretty arbitrary to me, just to serve as a reasonable default.

NOTE 1
~~~~~~

for two streams with max_pkt_size=3072 (worst case) both time
allocation would be 60us+60us=120us which is 96% periodic bandwidth
leaving 4% for bulk and control.  Alan Stern suggested that bulk then
would be problematic (less than 300*8 bittimes left per microframe), but
I think that is still enough for control traffic.

NOTE 2
~~~~~~

Sarah Sharp expressed concern that maxing out periodic bandwidth
could lead to vendor-specific hardware bugs on host controllers, because

> It's entirely possible that you'll run into
> vendor-specific bugs if you try to pack the schedule with isochronous
> transfers.  I don't think any hardware designer would seriously test or
> validate their hardware with a schedule that is basically a violation of
> the USB bus spec (more than 80% for periodic transfers).

So far I've only tested this patch on my HP Mini 5103 with N10 chipeset

    kirr@mini:~$ lspci
    00:00.0 Host bridge: Intel Corporation N10 Family DMI Bridge
    00:02.0 VGA compatible controller: Intel Corporation N10 Family Integrated Graphics Controller
    00:02.1 Display controller: Intel Corporation N10 Family Integrated Graphics Controller
    00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 02)
    00:1c.0 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 1 (rev 02)
    00:1c.3 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 4 (rev 02)
    00:1d.0 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #1 (rev 02)
    00:1d.1 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #2 (rev 02)
    00:1d.2 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #3 (rev 02)
    00:1d.3 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #4 (rev 02)
    00:1d.7 USB Controller: Intel Corporation N10/ICH 7 Family USB2 EHCI Controller (rev 02)
    00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2)
    00:1f.0 ISA bridge: Intel Corporation NM10 Family LPC Controller (rev 02)
    00:1f.2 SATA controller: Intel Corporation N10/ICH7 Family SATA AHCI Controller (rev 02)
    01:00.0 Network controller: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN Controller (rev 01)
    02:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8059 PCI-E Gigabit Ethernet Controller (rev 11)

and the system works stable with 110us/uframe (~88%) isoc bandwith allocated for
above-mentioned isochronous transfers.

NOTE 3
~~~~~~

This feature is off by default. I mean max periodic bandwidth is set to
100us/uframe by default exactly as it was before the patch. So only those of us
who need the extreme settings are taking the risk - normal users who do not
alter uframe_periodic_max sysfs attribute should not see any change at all.

Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
---
 drivers/usb/host/ehci-hcd.c   |    6 ++
 drivers/usb/host/ehci-sched.c |   17 +++----
 drivers/usb/host/ehci-sysfs.c |  104 +++++++++++++++++++++++++++++++++++++++--
 drivers/usb/host/ehci.h       |    2 +
 4 files changed, 115 insertions(+), 14 deletions(-)

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 8306155..4ee62be 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -572,6 +572,12 @@ static int ehci_init(struct usb_hcd *hcd)
 	hcc_params = ehci_readl(ehci, &ehci->caps->hcc_params);
 
 	/*
+	 * by default set standard 80% (== 100 usec/uframe) max periodic
+	 * bandwidth as required by USB 2.0
+	 */
+	ehci->uframe_periodic_max = 100;
+
+	/*
 	 * hw default: 1K periodic list heads, one per frame.
 	 * periodic_size can shrink by USBCMD update if hcc_params allows.
 	 */
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 6c9fbe3..2abf854 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -172,7 +172,7 @@ periodic_usecs (struct ehci_hcd *ehci, unsigned frame, unsigned uframe)
 		}
 	}
 #ifdef	DEBUG
-	if (usecs > 100)
+	if (usecs > ehci->uframe_periodic_max)
 		ehci_err (ehci, "uframe %d sched overrun: %d usecs\n",
 			frame * 8 + uframe, usecs);
 #endif
@@ -709,11 +709,8 @@ static int check_period (
 	if (uframe >= 8)
 		return 0;
 
-	/*
-	 * 80% periodic == 100 usec/uframe available
-	 * convert "usecs we need" to "max already claimed"
-	 */
-	usecs = 100 - usecs;
+	/* convert "usecs we need" to "max already claimed" */
+	usecs = ehci->uframe_periodic_max - usecs;
 
 	/* we "know" 2 and 4 uframe intervals were rejected; so
 	 * for period 0, check _every_ microframe in the schedule.
@@ -1286,9 +1283,9 @@ itd_slot_ok (
 {
 	uframe %= period;
 	do {
-		/* can't commit more than 80% periodic == 100 usec */
+		/* can't commit more than uframe_periodic_max usec */
 		if (periodic_usecs (ehci, uframe >> 3, uframe & 0x7)
-				> (100 - usecs))
+				> (ehci->uframe_periodic_max - usecs))
 			return 0;
 
 		/* we know urb->interval is 2^N uframes */
@@ -1345,7 +1342,7 @@ sitd_slot_ok (
 #endif
 
 		/* check starts (OUT uses more than one) */
-		max_used = 100 - stream->usecs;
+		max_used = ehci->uframe_periodic_max - stream->usecs;
 		for (tmp = stream->raw_mask & 0xff; tmp; tmp >>= 1, uf++) {
 			if (periodic_usecs (ehci, frame, uf) > max_used)
 				return 0;
@@ -1354,7 +1351,7 @@ sitd_slot_ok (
 		/* for IN, check CSPLIT */
 		if (stream->c_usecs) {
 			uf = uframe & 7;
-			max_used = 100 - stream->c_usecs;
+			max_used = ehci->uframe_periodic_max - stream->c_usecs;
 			do {
 				tmp = 1 << uf;
 				tmp <<= 8;
diff --git a/drivers/usb/host/ehci-sysfs.c b/drivers/usb/host/ehci-sysfs.c
index 29824a9..14ced00 100644
--- a/drivers/usb/host/ehci-sysfs.c
+++ b/drivers/usb/host/ehci-sysfs.c
@@ -74,21 +74,117 @@ static ssize_t store_companion(struct device *dev,
 }
 static DEVICE_ATTR(companion, 0644, show_companion, store_companion);
 
+
+/*
+ * Display / Set uframe_periodic_max
+ */
+static ssize_t show_uframe_periodic_max(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct ehci_hcd		*ehci;
+	int			n;
+
+	ehci = hcd_to_ehci(bus_to_hcd(dev_get_drvdata(dev)));
+	n = scnprintf(buf, PAGE_SIZE, "%d\n", ehci->uframe_periodic_max);
+	return n;
+}
+
+
+static ssize_t store_uframe_periodic_max(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct ehci_hcd		*ehci;
+	unsigned		uframe_periodic_max;
+	unsigned		frame, uframe;
+	unsigned short		allocated_max;
+	unsigned long		flags;
+	ssize_t			ret;
+
+	ehci = hcd_to_ehci(bus_to_hcd(dev_get_drvdata(dev)));
+	if (kstrtouint(buf, 0, &uframe_periodic_max) < 0)
+		return -EINVAL;
+
+	if (uframe_periodic_max < 100 || uframe_periodic_max >= 125) {
+		ehci_info(ehci, "rejecting invalid request for "
+				"uframe_periodic_max=%u\n", uframe_periodic_max);
+		return -EINVAL;
+	}
+
+	ret = -EINVAL;
+
+	/*
+	 * lock, so that our checking does not race with possible periodic
+	 * bandwidth allocation through submitting new urbs.
+	 */
+	spin_lock_irqsave (&ehci->lock, flags);
+
+	/*
+	 * for request to decrease max periodic bandwidth, we have to check
+	 * every microframe in the schedule to see whether the decrease is
+	 * possible.
+	 */
+	if (uframe_periodic_max < ehci->uframe_periodic_max) {
+		allocated_max = 0;
+
+		for (frame = 0; frame < ehci->periodic_size; ++frame)
+			for (uframe = 0; uframe < 7; ++uframe)
+				allocated_max = max(allocated_max,
+						    periodic_usecs (ehci, frame, uframe));
+
+		if (allocated_max > uframe_periodic_max) {
+			ehci_info(ehci,
+				"cannot decrease uframe_periodic_max becase "
+				"periodic bandwidth is already allocated "
+				"(%u > %u)\n",
+				allocated_max, uframe_periodic_max);
+			goto out_unlock;
+		}
+	}
+
+	/* increasing is always ok */
+
+	ehci_info(ehci, "setting max periodic bandwidth to %u%% "
+			"(== %u usec/uframe)\n",
+			100*uframe_periodic_max/125, uframe_periodic_max);
+
+	if (uframe_periodic_max != 100)
+		ehci_warn(ehci, "max periodic bandwidth set is non-standard\n");
+
+	ehci->uframe_periodic_max = uframe_periodic_max;
+	ret = count;
+
+out_unlock:
+	spin_unlock_irqrestore (&ehci->lock, flags);
+	return ret;
+}
+static DEVICE_ATTR(uframe_periodic_max, 0644, show_uframe_periodic_max, store_uframe_periodic_max);
+
+
 static inline int create_sysfs_files(struct ehci_hcd *ehci)
 {
+	struct device	*controller = ehci_to_hcd(ehci)->self.controller;
 	int	i = 0;
 
 	/* with integrated TT there is no companion! */
 	if (!ehci_is_TDI(ehci))
-		i = device_create_file(ehci_to_hcd(ehci)->self.controller,
-				       &dev_attr_companion);
+		i = device_create_file(controller, &dev_attr_companion);
+	if (i)
+		goto out;
+
+	i = device_create_file(controller, &dev_attr_uframe_periodic_max);
+out:
 	return i;
 }
 
 static inline void remove_sysfs_files(struct ehci_hcd *ehci)
 {
+	struct device	*controller = ehci_to_hcd(ehci)->self.controller;
+
 	/* with integrated TT there is no companion! */
 	if (!ehci_is_TDI(ehci))
-		device_remove_file(ehci_to_hcd(ehci)->self.controller,
-				   &dev_attr_companion);
+		device_remove_file(controller, &dev_attr_companion);
+
+	device_remove_file(controller, &dev_attr_uframe_periodic_max);
 }
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index bd6ff48..fa3129f 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -87,6 +87,8 @@ struct ehci_hcd {			/* one per controller */
 	union ehci_shadow	*pshadow;	/* mirror hw periodic table */
 	int			next_uframe;	/* scan periodic, start here */
 	unsigned		periodic_sched;	/* periodic activity count */
+	unsigned		uframe_periodic_max; /* max periodic time per uframe */
+
 
 	/* list of itds & sitds completed while clock_frame was still active */
 	struct list_head	cached_itd_list;
-- 
1.7.6.rc3

Re: [PATCH v3 2/2] USB: EHCI: Allow users to override 80% max periodic bandwidth

[Greg KH]

On Fri, Jul 01, 2011 at 03:47:11PM +0400, Kirill Smelkov wrote:
>  drivers/usb/host/ehci-sysfs.c |  104 +++++++++++++++++++++++++++++++++++++++--

As you are adding new sysfs files, it is required that you also add new
entries in the Documentation/ABI/ directory.

Please do that for these files so that people have an idea of what they
are, and how to use them.

Care to redo this series with that change?

thanks,

greg k-h

Re: [PATCH v3 2/2] USB: EHCI: Allow users to override 80% max periodic bandwidth

[Kirill Smelkov]

On Fri, Jul 01, 2011 at 02:24:27PM -0700, Greg KH wrote:
> On Fri, Jul 01, 2011 at 03:47:11PM +0400, Kirill Smelkov wrote:
> >  drivers/usb/host/ehci-sysfs.c |  104 +++++++++++++++++++++++++++++++++++++++--
> 
> As you are adding new sysfs files, it is required that you also add new
> entries in the Documentation/ABI/ directory.
> 
> Please do that for these files so that people have an idea of what they
> are, and how to use them.
> 
> Care to redo this series with that change?

Sure, I'll post v4 with documentation included.

Thanks,
Kirill