[PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[Gianluca Gennari]

(was: Re: PCTV 290e page allocation failure)

On MIPS/ARM set-top-boxes, as well as old x86 PCs, memory allocation failures
in the em28xx driver are common, due to memory fragmentation over time, that
makes impossible to allocate large chunks of coherent memory.
A typical system with 256/512 MB of RAM fails after just 1 day of uptime (see
the old thread for detailed reports and crashlogs).

In fact, the em28xx driver allocates memory for USB isoc transfers at runtime,
as opposite to the dvb-usb drivers that allocates the USB buffers when the
device is initialized, and frees them when the device is disconnected.

Moreover, in digital mode the USB isoc transfer buffers are freed, allocated
and cleared every time the user selects a new channel, wasting time and
resources.

This patch solves both problems by allocating DVB isoc transfer buffers in
em28xx_usb_probe(), and freeing them in em28xx_usb_disconnect().
In fact, the buffers size and number depend only on the max USB packet size
that is parsed from the USB descriptors in em28xx_usb_probe(), so it can
never change for a given device.

This approach makes no sense in analog mode (as the buffer size depends on
the alternate mode selected at runtime), the patch creates two separate sets
of buffers for digital and analog modes.

For digital-only devices, USB buffers are created when the device is probed
and freed when the device is disconnected.
For analog-only devices, nothing changes: isoc buffers are created at runtime.
For hybrid devices, two sets of buffers are maintained: the digital-mode
buffers are created when the device is probed, and freed when the device is
disconnected; analog-mode buffers are created/destroyed at runtime as before.
So, in analog mode, digital and analog buffers coexists at the same time: this
can be justified by the fact that digital mode is by far more commonly used
nowadays, so it makes sense to optimize the driver for this use case scenario.

The patch has been tested in the last few days on a x86 PC and a MIPS
set-top-box, with the PCTV 290e (digital only) and the Terratec Hybrid XS
(hybrid device). With the latter, I switched several times between analog and
digital mode (Kaffeine/TvTime) with no issue at all.
I unplugged/plugged the devices several times with no problem.
Also, after over 3 days of normal usage in the MPIS set-top-box, the PCTV 290e
was still up and running.

Signed-off-by: Gianluca Gennari <gennarone@gmail.com>
---
 drivers/media/video/em28xx/em28xx-cards.c |   16 +++-
 drivers/media/video/em28xx/em28xx-core.c  |  145 +++++++++++++++++++----------
 drivers/media/video/em28xx/em28xx-dvb.c   |   14 +--
 drivers/media/video/em28xx/em28xx-video.c |   10 +-
 drivers/media/video/em28xx/em28xx.h       |   23 ++++-
 5 files changed, 142 insertions(+), 66 deletions(-)

diff --git a/drivers/media/video/em28xx/em28xx-cards.c b/drivers/media/video/em28xx/em28xx-cards.c
index 2aa772a..5c06bac 100644
--- a/drivers/media/video/em28xx/em28xx-cards.c
+++ b/drivers/media/video/em28xx/em28xx-cards.c
@@ -3307,6 +3307,17 @@ static int em28xx_usb_probe(struct usb_interface *interface,
 		goto unlock_and_free;
 	}
 
+	if (has_dvb) {
+		/* pre-allocate DVB isoc transfer buffers */
+		retval = em28xx_alloc_isoc(dev, EM28XX_DIGITAL_MODE,
+					   EM28XX_DVB_MAX_PACKETS,
+					   EM28XX_DVB_NUM_BUFS,
+					   dev->dvb_max_pkt_size);
+		if (retval) {
+			goto unlock_and_free;
+		}
+	}
+
 	request_modules(dev);
 
 	/* Should be the last thing to do, to avoid newer udev's to
@@ -3379,7 +3390,7 @@ static void em28xx_usb_disconnect(struct usb_interface *interface)
 		     video_device_node_name(dev->vdev));
 
 		dev->state |= DEV_MISCONFIGURED;
-		em28xx_uninit_isoc(dev);
+		em28xx_uninit_isoc(dev, dev->mode);
 		dev->state |= DEV_DISCONNECTED;
 		wake_up_interruptible(&dev->wait_frame);
 		wake_up_interruptible(&dev->wait_stream);
@@ -3388,6 +3399,9 @@ static void em28xx_usb_disconnect(struct usb_interface *interface)
 		em28xx_release_resources(dev);
 	}
 
+	/* free DVB isoc buffers */
+	em28xx_uninit_isoc(dev, EM28XX_DIGITAL_MODE);
+
 	mutex_unlock(&dev->lock);
 
 	em28xx_close_extension(dev);
diff --git a/drivers/media/video/em28xx/em28xx-core.c b/drivers/media/video/em28xx/em28xx-core.c
index 0aacc96..53a9fb9 100644
--- a/drivers/media/video/em28xx/em28xx-core.c
+++ b/drivers/media/video/em28xx/em28xx-core.c
@@ -666,6 +666,7 @@ int em28xx_capture_start(struct em28xx *dev, int start)
 
 	return rc;
 }
+EXPORT_SYMBOL_GPL(em28xx_capture_start);
 
 int em28xx_vbi_supported(struct em28xx *dev)
 {
@@ -961,146 +962,192 @@ static void em28xx_irq_callback(struct urb *urb)
 /*
  * Stop and Deallocate URBs
  */
-void em28xx_uninit_isoc(struct em28xx *dev)
+void em28xx_uninit_isoc(struct em28xx *dev, enum em28xx_mode mode)
 {
 	struct urb *urb;
+	struct em28xx_usb_isoc_bufs *isoc_bufs;
 	int i;
 
-	em28xx_isocdbg("em28xx: called em28xx_uninit_isoc\n");
+	em28xx_isocdbg("em28xx: called em28xx_uninit_isoc in mode %d\n", mode);
+
+	if (mode == EM28XX_DIGITAL_MODE)
+		isoc_bufs = &dev->isoc_ctl.digital_bufs;
+	else
+		isoc_bufs = &dev->isoc_ctl.analog_bufs;
 
 	dev->isoc_ctl.nfields = -1;
-	for (i = 0; i < dev->isoc_ctl.num_bufs; i++) {
-		urb = dev->isoc_ctl.urb[i];
+	for (i = 0; i < isoc_bufs->num_bufs; i++) {
+		urb = isoc_bufs->urb[i];
 		if (urb) {
 			if (!irqs_disabled())
 				usb_kill_urb(urb);
 			else
 				usb_unlink_urb(urb);
 
-			if (dev->isoc_ctl.transfer_buffer[i]) {
+			if (isoc_bufs->transfer_buffer[i]) {
 				usb_free_coherent(dev->udev,
 					urb->transfer_buffer_length,
-					dev->isoc_ctl.transfer_buffer[i],
+					isoc_bufs->transfer_buffer[i],
 					urb->transfer_dma);
 			}
 			usb_free_urb(urb);
-			dev->isoc_ctl.urb[i] = NULL;
+			isoc_bufs->urb[i] = NULL;
 		}
-		dev->isoc_ctl.transfer_buffer[i] = NULL;
+		isoc_bufs->transfer_buffer[i] = NULL;
 	}
 
-	kfree(dev->isoc_ctl.urb);
-	kfree(dev->isoc_ctl.transfer_buffer);
+	kfree(isoc_bufs->urb);
+	kfree(isoc_bufs->transfer_buffer);
 
-	dev->isoc_ctl.urb = NULL;
-	dev->isoc_ctl.transfer_buffer = NULL;
-	dev->isoc_ctl.num_bufs = 0;
+	isoc_bufs->urb = NULL;
+	isoc_bufs->transfer_buffer = NULL;
+	isoc_bufs->num_bufs = 0;
 
 	em28xx_capture_start(dev, 0);
 }
 EXPORT_SYMBOL_GPL(em28xx_uninit_isoc);
 
 /*
- * Allocate URBs and start IRQ
+ * Allocate URBs
  */
-int em28xx_init_isoc(struct em28xx *dev, int max_packets,
-		     int num_bufs, int max_pkt_size,
-		     int (*isoc_copy) (struct em28xx *dev, struct urb *urb))
+int em28xx_alloc_isoc(struct em28xx *dev, enum em28xx_mode mode,
+		      int max_packets, int num_bufs, int max_pkt_size)
 {
-	struct em28xx_dmaqueue *dma_q = &dev->vidq;
-	struct em28xx_dmaqueue *vbi_dma_q = &dev->vbiq;
+	struct em28xx_usb_isoc_bufs *isoc_bufs;
 	int i;
 	int sb_size, pipe;
 	struct urb *urb;
 	int j, k;
-	int rc;
 
-	em28xx_isocdbg("em28xx: called em28xx_prepare_isoc\n");
+	em28xx_isocdbg("em28xx: called em28xx_alloc_isoc in mode %d\n", mode);
+
+	if (mode == EM28XX_DIGITAL_MODE)
+		isoc_bufs = &dev->isoc_ctl.digital_bufs;
+	else
+		isoc_bufs = &dev->isoc_ctl.analog_bufs;
 
 	/* De-allocates all pending stuff */
-	em28xx_uninit_isoc(dev);
+	em28xx_uninit_isoc(dev, mode);
 
-	dev->isoc_ctl.isoc_copy = isoc_copy;
-	dev->isoc_ctl.num_bufs = num_bufs;
+	isoc_bufs->num_bufs = num_bufs;
 
-	dev->isoc_ctl.urb = kzalloc(sizeof(void *)*num_bufs,  GFP_KERNEL);
-	if (!dev->isoc_ctl.urb) {
+	isoc_bufs->urb = kzalloc(sizeof(void *)*num_bufs,  GFP_KERNEL);
+	if (!isoc_bufs->urb) {
 		em28xx_errdev("cannot alloc memory for usb buffers\n");
 		return -ENOMEM;
 	}
 
-	dev->isoc_ctl.transfer_buffer = kzalloc(sizeof(void *)*num_bufs,
-					      GFP_KERNEL);
-	if (!dev->isoc_ctl.transfer_buffer) {
+	isoc_bufs->transfer_buffer = kzalloc(sizeof(void *)*num_bufs,
+					     GFP_KERNEL);
+	if (!isoc_bufs->transfer_buffer) {
 		em28xx_errdev("cannot allocate memory for usb transfer\n");
-		kfree(dev->isoc_ctl.urb);
+		kfree(isoc_bufs->urb);
 		return -ENOMEM;
 	}
 
-	dev->isoc_ctl.max_pkt_size = max_pkt_size;
+	isoc_bufs->max_pkt_size = max_pkt_size;
+	isoc_bufs->num_packets = max_packets;
 	dev->isoc_ctl.vid_buf = NULL;
 	dev->isoc_ctl.vbi_buf = NULL;
 
-	sb_size = max_packets * dev->isoc_ctl.max_pkt_size;
+	sb_size = isoc_bufs->num_packets * isoc_bufs->max_pkt_size;
 
 	/* allocate urbs and transfer buffers */
-	for (i = 0; i < dev->isoc_ctl.num_bufs; i++) {
-		urb = usb_alloc_urb(max_packets, GFP_KERNEL);
+	for (i = 0; i < isoc_bufs->num_bufs; i++) {
+		urb = usb_alloc_urb(isoc_bufs->num_packets, GFP_KERNEL);
 		if (!urb) {
 			em28xx_err("cannot alloc isoc_ctl.urb %i\n", i);
-			em28xx_uninit_isoc(dev);
+			em28xx_uninit_isoc(dev, mode);
 			return -ENOMEM;
 		}
-		dev->isoc_ctl.urb[i] = urb;
+		isoc_bufs->urb[i] = urb;
 
-		dev->isoc_ctl.transfer_buffer[i] = usb_alloc_coherent(dev->udev,
+		isoc_bufs->transfer_buffer[i] = usb_alloc_coherent(dev->udev,
 			sb_size, GFP_KERNEL, &urb->transfer_dma);
-		if (!dev->isoc_ctl.transfer_buffer[i]) {
+		if (!isoc_bufs->transfer_buffer[i]) {
 			em28xx_err("unable to allocate %i bytes for transfer"
 					" buffer %i%s\n",
 					sb_size, i,
 					in_interrupt() ? " while in int" : "");
-			em28xx_uninit_isoc(dev);
+			em28xx_uninit_isoc(dev, mode);
 			return -ENOMEM;
 		}
-		memset(dev->isoc_ctl.transfer_buffer[i], 0, sb_size);
+		memset(isoc_bufs->transfer_buffer[i], 0, sb_size);
 
 		/* FIXME: this is a hack - should be
 			'desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK'
 			should also be using 'desc.bInterval'
 		 */
 		pipe = usb_rcvisocpipe(dev->udev,
-				       dev->mode == EM28XX_ANALOG_MODE ?
+				       mode == EM28XX_ANALOG_MODE ?
 				       EM28XX_EP_ANALOG : EM28XX_EP_DIGITAL);
 
 		usb_fill_int_urb(urb, dev->udev, pipe,
-				 dev->isoc_ctl.transfer_buffer[i], sb_size,
+				 isoc_bufs->transfer_buffer[i], sb_size,
 				 em28xx_irq_callback, dev, 1);
 
-		urb->number_of_packets = max_packets;
+		urb->number_of_packets = isoc_bufs->num_packets;
 		urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
 
 		k = 0;
-		for (j = 0; j < max_packets; j++) {
+		for (j = 0; j < isoc_bufs->num_packets; j++) {
 			urb->iso_frame_desc[j].offset = k;
 			urb->iso_frame_desc[j].length =
-						dev->isoc_ctl.max_pkt_size;
-			k += dev->isoc_ctl.max_pkt_size;
+						isoc_bufs->max_pkt_size;
+			k += isoc_bufs->max_pkt_size;
 		}
 	}
 
+	return 0;
+}
+EXPORT_SYMBOL_GPL(em28xx_alloc_isoc);
+
+/*
+ * Allocate URBs and start IRQ
+ */
+int em28xx_init_isoc(struct em28xx *dev, enum em28xx_mode mode,
+		     int max_packets, int num_bufs, int max_pkt_size,
+		     int (*isoc_copy) (struct em28xx *dev, struct urb *urb))
+{
+	struct em28xx_dmaqueue *dma_q = &dev->vidq;
+	struct em28xx_dmaqueue *vbi_dma_q = &dev->vbiq;
+	struct em28xx_usb_isoc_bufs *isoc_bufs;
+	int i;
+	int rc;
+	int alloc;
+
+	em28xx_isocdbg("em28xx: called em28xx_init_isoc in mode %d\n", mode);
+
+	dev->isoc_ctl.isoc_copy = isoc_copy;
+
+	if (mode == EM28XX_DIGITAL_MODE) {
+		isoc_bufs = &dev->isoc_ctl.digital_bufs;
+		/* no need to free/alloc isoc buffers in digital mode */
+		alloc = 0;
+	} else {
+		isoc_bufs = &dev->isoc_ctl.analog_bufs;
+		alloc = 1;
+	}
+
+	if (alloc) {
+		rc = em28xx_alloc_isoc(dev, mode, max_packets,
+				       num_bufs, max_pkt_size);
+		if (rc)
+			return rc;
+	}
+
 	init_waitqueue_head(&dma_q->wq);
 	init_waitqueue_head(&vbi_dma_q->wq);
 
 	em28xx_capture_start(dev, 1);
 
 	/* submit urbs and enables IRQ */
-	for (i = 0; i < dev->isoc_ctl.num_bufs; i++) {
-		rc = usb_submit_urb(dev->isoc_ctl.urb[i], GFP_ATOMIC);
+	for (i = 0; i < isoc_bufs->num_bufs; i++) {
+		rc = usb_submit_urb(isoc_bufs->urb[i], GFP_ATOMIC);
 		if (rc) {
 			em28xx_err("submit of urb %i failed (error=%i)\n", i,
 				   rc);
-			em28xx_uninit_isoc(dev);
+			em28xx_uninit_isoc(dev, mode);
 			return rc;
 		}
 	}
diff --git a/drivers/media/video/em28xx/em28xx-dvb.c b/drivers/media/video/em28xx/em28xx-dvb.c
index aabbf48..fbd9010 100644
--- a/drivers/media/video/em28xx/em28xx-dvb.c
+++ b/drivers/media/video/em28xx/em28xx-dvb.c
@@ -61,9 +61,6 @@ if (debug >= level) 						\
 	printk(KERN_DEBUG "%s/2-dvb: " fmt, dev->name, ## arg);	\
 } while (0)
 
-#define EM28XX_DVB_NUM_BUFS 5
-#define EM28XX_DVB_MAX_PACKETS 64
-
 struct em28xx_dvb {
 	struct dvb_frontend        *fe[2];
 
@@ -172,20 +169,21 @@ static int em28xx_start_streaming(struct em28xx_dvb *dvb)
 	max_dvb_packet_size = dev->dvb_max_pkt_size;
 	if (max_dvb_packet_size < 0)
 		return max_dvb_packet_size;
-	dprintk(1, "Using %d buffers each with %d bytes\n",
+	dprintk(1, "Using %d buffers each with %d x %d bytes\n",
 		EM28XX_DVB_NUM_BUFS,
+		EM28XX_DVB_MAX_PACKETS,
 		max_dvb_packet_size);
 
-	return em28xx_init_isoc(dev, EM28XX_DVB_MAX_PACKETS,
-				EM28XX_DVB_NUM_BUFS, max_dvb_packet_size,
-				em28xx_dvb_isoc_copy);
+	return em28xx_init_isoc(dev, EM28XX_DIGITAL_MODE,
+				EM28XX_DVB_MAX_PACKETS, EM28XX_DVB_NUM_BUFS,
+				max_dvb_packet_size, em28xx_dvb_isoc_copy);
 }
 
 static int em28xx_stop_streaming(struct em28xx_dvb *dvb)
 {
 	struct em28xx *dev = dvb->adapter.priv;
 
-	em28xx_uninit_isoc(dev);
+	em28xx_capture_start(dev, 0);
 
 	em28xx_set_mode(dev, EM28XX_SUSPEND);
 
diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c
index 613300b..324b695 100644
--- a/drivers/media/video/em28xx/em28xx-video.c
+++ b/drivers/media/video/em28xx/em28xx-video.c
@@ -760,17 +760,19 @@ buffer_prepare(struct videobuf_queue *vq, struct videobuf_buffer *vb,
 			goto fail;
 	}
 
-	if (!dev->isoc_ctl.num_bufs)
+	if (!dev->isoc_ctl.analog_bufs.num_bufs)
 		urb_init = 1;
 
 	if (urb_init) {
 		if (em28xx_vbi_supported(dev) == 1)
-			rc = em28xx_init_isoc(dev, EM28XX_NUM_PACKETS,
+			rc = em28xx_init_isoc(dev, EM28XX_ANALOG_MODE,
+					      EM28XX_NUM_PACKETS,
 					      EM28XX_NUM_BUFS,
 					      dev->max_pkt_size,
 					      em28xx_isoc_copy_vbi);
 		else
-			rc = em28xx_init_isoc(dev, EM28XX_NUM_PACKETS,
+			rc = em28xx_init_isoc(dev, EM28XX_ANALOG_MODE,
+					      EM28XX_NUM_PACKETS,
 					      EM28XX_NUM_BUFS,
 					      dev->max_pkt_size,
 					      em28xx_isoc_copy);
@@ -2267,7 +2269,7 @@ static int em28xx_v4l2_close(struct file *filp)
 		v4l2_device_call_all(&dev->v4l2_dev, 0, core, s_power, 0);
 
 		/* do this before setting alternate! */
-		em28xx_uninit_isoc(dev);
+		em28xx_uninit_isoc(dev, EM28XX_ANALOG_MODE);
 		em28xx_set_mode(dev, EM28XX_SUSPEND);
 
 		/* set alternate 0 */
diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h
index 22e252b..2ae6815 100644
--- a/drivers/media/video/em28xx/em28xx.h
+++ b/drivers/media/video/em28xx/em28xx.h
@@ -151,12 +151,14 @@
 
 /* number of buffers for isoc transfers */
 #define EM28XX_NUM_BUFS 5
+#define EM28XX_DVB_NUM_BUFS 5
 
 /* number of packets for each buffer
    windows requests only 64 packets .. so we better do the same
    this is what I found out for all alternate numbers there!
  */
 #define EM28XX_NUM_PACKETS 64
+#define EM28XX_DVB_MAX_PACKETS 64
 
 #define EM28XX_INTERLACED_DEFAULT 1
 
@@ -197,10 +199,13 @@ enum em28xx_mode {
 
 struct em28xx;
 
-struct em28xx_usb_isoc_ctl {
+struct em28xx_usb_isoc_bufs {
 		/* max packet size of isoc transaction */
 	int				max_pkt_size;
 
+		/* number of packets in each buffer */
+	int				num_packets;
+
 		/* number of allocated urbs */
 	int				num_bufs;
 
@@ -209,6 +214,14 @@ struct em28xx_usb_isoc_ctl {
 
 		/* transfer buffers for isoc transfer */
 	char				**transfer_buffer;
+};
+
+struct em28xx_usb_isoc_ctl {
+		/* isoc transfer buffers for analog mode */
+	struct em28xx_usb_isoc_bufs	analog_bufs;
+
+		/* isoc transfer buffers for digital mode */
+	struct em28xx_usb_isoc_bufs	digital_bufs;
 
 		/* Last buffer command and region */
 	u8				cmd;
@@ -676,10 +689,12 @@ int em28xx_vbi_supported(struct em28xx *dev);
 int em28xx_set_outfmt(struct em28xx *dev);
 int em28xx_resolution_set(struct em28xx *dev);
 int em28xx_set_alternate(struct em28xx *dev);
-int em28xx_init_isoc(struct em28xx *dev, int max_packets,
-		     int num_bufs, int max_pkt_size,
+int em28xx_alloc_isoc(struct em28xx *dev, enum em28xx_mode mode,
+		      int max_packets, int num_bufs, int max_pkt_size);
+int em28xx_init_isoc(struct em28xx *dev, enum em28xx_mode mode,
+		     int max_packets, int num_bufs, int max_pkt_size,
 		     int (*isoc_copy) (struct em28xx *dev, struct urb *urb));
-void em28xx_uninit_isoc(struct em28xx *dev);
+void em28xx_uninit_isoc(struct em28xx *dev, enum em28xx_mode mode);
 int em28xx_isoc_dvb_max_packetsize(struct em28xx *dev);
 int em28xx_set_mode(struct em28xx *dev, enum em28xx_mode set_mode);
 int em28xx_gpio_set(struct em28xx *dev, struct em28xx_reg_seq *gpio);
-- 
1.7.0.4

[PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[Chris Rankin]

Gianluca,

One quick comment about your patch; I've noticed that you've declared two new 
"GPL only" symbols:

EXPORT_SYMBOL_GPL(em28xx_capture_start);
EXPORT_SYMBOL_GPL(em28xx_alloc_isoc);

I'm not sure what the exact policy is with GPL symbols, but I do know what Al 
Viro posted recently on the subject:

http://thread.gmane.org/gmane.linux.file-systems/61372

Do we really need EXPORT_SYMBOL_GPL() here?

Cheers,
Chris

Re: [PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[Gianluca Gennari]

Il 20/02/2012 00:46, Chris Rankin ha scritto:
> Gianluca,
> 
> One quick comment about your patch; I've noticed that you've declared
> two new "GPL only" symbols:
> 
> EXPORT_SYMBOL_GPL(em28xx_capture_start);
> EXPORT_SYMBOL_GPL(em28xx_alloc_isoc);
> 
> I'm not sure what the exact policy is with GPL symbols, but I do know
> what Al Viro posted recently on the subject:
> 
> http://thread.gmane.org/gmane.linux.file-systems/61372
> 
> Do we really need EXPORT_SYMBOL_GPL() here?
> 
> Cheers,
> Chris
> 

Hi Chris,
thanks for the comment.
The two new symbols are used in place of the old em28xx_init_isoc and
em28xx_uninit_isoc in two different modules (em28xx and em28xx-dvb).
Since the old symbols are exported through EXPORT_SYMBOL_GPL(), I did
the same with the new ones.
This choice should not break any non-GPL module, as this symbols are
meant to be used only in the em28xx* modules, just like the old ones.

Regards,
Gianluca

Re: [PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[Andy Furniss]

Gianluca Gennari wrote:
> (was: Re: PCTV 290e page allocation failure)
>
> On MIPS/ARM set-top-boxes, as well as old x86 PCs, memory allocation failures
> in the em28xx driver are common, due to memory fragmentation over time, that
> makes impossible to allocate large chunks of coherent memory.
> A typical system with 256/512 MB of RAM fails after just 1 day of uptime (see
> the old thread for detailed reports and crashlogs).
>
> In fact, the em28xx driver allocates memory for USB isoc transfers at runtime,
> as opposite to the dvb-usb drivers that allocates the USB buffers when the
> device is initialized, and frees them when the device is disconnected.
>
> Moreover, in digital mode the USB isoc transfer buffers are freed, allocated
> and cleared every time the user selects a new channel, wasting time and
> resources.

Does this patch have a chance of getting in?

I am still having to flush caches before use. If you want more testing I 
can give it a go. I didn't earlier as I didn't have a git to apply it to 
and thought it was going to get in anyway.

Re: [PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[Gianluca Gennari]

Il 16/03/2012 01:25, Andy Furniss ha scritto:

> Does this patch have a chance of getting in?
> 
> I am still having to flush caches before use. If you want more testing I
> can give it a go. I didn't earlier as I didn't have a git to apply it to
> and thought it was going to get in anyway.

Hi Andy,
the patch is already in the current media_build tree and is queued for
kernel 3.4.

Regards,
Gianluca

Re: [PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[Gianluca Gennari]

Il 16/03/2012 01:25, Andy Furniss ha scritto:
> 
> Does this patch have a chance of getting in?
> 
> I am still having to flush caches before use. If you want more testing I
> can give it a go. I didn't earlier as I didn't have a git to apply it to
> and thought it was going to get in anyway.
> 

Hi Andy,
the patch is already in the current media_build tree and is queued for
kernel 3.4.

Regards,
Gianluca

Re: [PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[Andy Furniss]

Gianluca Gennari wrote:
> Il 16/03/2012 01:25, Andy Furniss ha scritto:
>>
>> Does this patch have a chance of getting in?
>>
>> I am still having to flush caches before use. If you want more testing I
>> can give it a go. I didn't earlier as I didn't have a git to apply it to
>> and thought it was going to get in anyway.
>>
>
> Hi Andy,
> the patch is already in the current media_build tree and is queued for
> kernel 3.4.

Ahh, I'll give that a try, thanks.

Re: [PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[Andy Furniss]

Andy Furniss wrote:
> Gianluca Gennari wrote:

>> Hi Andy,
>> the patch is already in the current media_build tree and is queued for
>> kernel 3.4.
>
> Ahh, I'll give that a try, thanks.

Seems to be working OK so far, I had to avoid building radio to get it 
to compile.

Are these just informational - I get five every time I tune (barring the 
first time IIRC)

Mar 16 14:56:58 noki kernel: ehci_hcd 0000:01:0a.2: shutdown urb 
ced2d000 ep4in-iso
Mar 16 14:56:58 noki kernel: ehci_hcd 0000:01:0a.2: shutdown urb 
ced2d800 ep4in-iso
Mar 16 14:56:58 noki kernel: ehci_hcd 0000:01:0a.2: shutdown urb 
cec3f800 ep4in-iso
Mar 16 14:56:58 noki kernel: ehci_hcd 0000:01:0a.2: shutdown urb 
ced2c000 ep4in-iso
Mar 16 14:56:58 noki kernel: ehci_hcd 0000:01:0a.2: shutdown urb 
ced2c800 ep4in-iso

Re: [PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[Gianluca Gennari]

Il 16/03/2012 16:05, Andy Furniss ha scritto:
> Andy Furniss wrote:
>> Gianluca Gennari wrote:
> 
>>> Hi Andy,
>>> the patch is already in the current media_build tree and is queued for
>>> kernel 3.4.
>>
>> Ahh, I'll give that a try, thanks.
> 
> Seems to be working OK so far, I had to avoid building radio to get it
> to compile.
> 
> Are these just informational - I get five every time I tune (barring the
> first time IIRC)
> 
> Mar 16 14:56:58 noki kernel: ehci_hcd 0000:01:0a.2: shutdown urb
> ced2d000 ep4in-iso
> Mar 16 14:56:58 noki kernel: ehci_hcd 0000:01:0a.2: shutdown urb
> ced2d800 ep4in-iso
> Mar 16 14:56:58 noki kernel: ehci_hcd 0000:01:0a.2: shutdown urb
> cec3f800 ep4in-iso
> Mar 16 14:56:58 noki kernel: ehci_hcd 0000:01:0a.2: shutdown urb
> ced2c000 ep4in-iso
> Mar 16 14:56:58 noki kernel: ehci_hcd 0000:01:0a.2: shutdown urb
> ced2c800 ep4in-iso

Looks like some innocuous logging from the ehci_hcd driver. I've never
seen it because I'm not using the ehci_hcd module on my systems.
When you tune a new channel, the USB transfer is stopped (with the URBs
still alive, so the driver "shuts down" them) and a new one is started.
Then the URBs are reused (instead of being deallocated/allocated
again/cleared as before) so they are resubmitted.

Regards,
Gianluca

Re: [PATCH] em28xx: pre-allocate DVB isoc transfer buffers

[Andy Furniss]

Gianluca Gennari wrote:
>> Andy Furniss wrote:
>> Mar 16 14:56:58 noki kernel: ehci_hcd 0000:01:0a.2: shutdown urb
>> ced2c800 ep4in-iso
>
> Looks like some innocuous logging from the ehci_hcd driver. I've never
> seen it because I'm not using the ehci_hcd module on my systems.
> When you tune a new channel, the USB transfer is stopped (with the URBs
> still alive, so the driver "shuts down" them) and a new one is started.
> Then the URBs are reused (instead of being deallocated/allocated
> again/cleared as before) so they are resubmitted.

Ok, I don't have any problems so far - I also probably have some 
verbose/debugging usb options enabled in my kernel so I suppose others 
may never see these.