Greg, is that patch on your list or did it get lost?
* Sebastian Andrzej Siewior | 2011-02-08 21:07:40 [+0100]:
>The document says:
>|2.1 Problem description
>| When at least two USB devices are simultaneously running, it is observed that
>| sometimes the INT corresponding to one of the USB devices stops occurring. This may
>| be observed sometimes with USB-to-serial or USB-to-network devices.
>| The problem is not noticed when only USB mass storage devices are running.
>|2.2 Implication
>| This issue is because of the clearing of the respective Done Map bit on reading the ATL
>| PTD Done Map register when an INT is generated by another PTD completion, but is not
>| found set on that read access. In this situation, the respective Done Map bit will remain
>| reset and no further INT will be asserted so the data transfer corresponding to that USB
>| device will stop.
>|2.3 Workaround
>| An SOF INT can be used instead of an ATL INT with polling on Done bits. A time-out can
>| be implemented and if a certain Done bit is never set, verification of the PTD completion
>| can be done by reading PTD contents (valid bit).
>| This is a proven workaround implemented in software.
>
>Russell King run into this with an USB-to-serial converter. This patch
>implements his suggestion to enable the high frequent SOF interrupt only
>at the time we have ATL packages queued. It goes even one step further
>and enables the SOF interrupt only if we have more than one ATL packet
>queued at the same time.
>
>Cc: <stable@xxxxxxxxxx> # [2.6.35.x, 2.6.36.x, 2.6.37.x]
>Tested-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
>Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
>---
>v1..v2: use the register offset instead of the value.
>v2..v3: change patch title
>
> drivers/usb/host/isp1760-hcd.c | 22 ++++++++++++++++------
> drivers/usb/host/isp1760-hcd.h | 1 +
> 2 files changed, 17 insertions(+), 6 deletions(-)
>
>diff --git a/drivers/usb/host/isp1760-hcd.c b/drivers/usb/host/isp1760-hcd.c
>index bdba8c5..c470cc8 100644
>--- a/drivers/usb/host/isp1760-hcd.c
>+++ b/drivers/usb/host/isp1760-hcd.c
>@@ -33,6 +33,7 @@ struct isp1760_hcd {
> struct inter_packet_info atl_ints[32];
> struct inter_packet_info int_ints[32];
> struct memory_chunk memory_pool[BLOCKS];
>+ u32 atl_queued;
>
> /* periodic schedule support */
> #define DEFAULT_I_TDPS 1024
>@@ -850,6 +851,11 @@ static void enqueue_an_ATL_packet(struct usb_hcd *hcd, struct isp1760_qh *qh,
> skip_map &= ~queue_entry;
> isp1760_writel(skip_map, hcd->regs + HC_ATL_PTD_SKIPMAP_REG);
>
>+ priv->atl_queued++;
>+ if (priv->atl_queued == 2)
>+ isp1760_writel(INTERRUPT_ENABLE_SOT_MASK,
>+ hcd->regs + HC_INTERRUPT_ENABLE);
>+
> buffstatus = isp1760_readl(hcd->regs + HC_BUFFER_STATUS_REG);
> buffstatus |= ATL_BUFFER;
> isp1760_writel(buffstatus, hcd->regs + HC_BUFFER_STATUS_REG);
>@@ -992,6 +998,7 @@ static void do_atl_int(struct usb_hcd *usb_hcd)
> u32 dw3;
>
> status = 0;
>+ priv->atl_queued--;
>
> queue_entry = __ffs(done_map);
> done_map &= ~(1 << queue_entry);
>@@ -1054,11 +1061,6 @@ static void do_atl_int(struct usb_hcd *usb_hcd)
> * device is not able to send data fast enough.
> * This happens mostly on slower hardware.
> */
>- printk(KERN_NOTICE "Reloading ptd %p/%p... qh %p read: "
>- "%d of %zu done: %08x cur: %08x\n", qtd,
>- urb, qh, PTD_XFERRED_LENGTH(dw3),
>- qtd->length, done_map,
>- (1 << queue_entry));
>
> /* RL counter = ERR counter */
> dw3 &= ~(0xf << 19);
>@@ -1086,6 +1088,11 @@ static void do_atl_int(struct usb_hcd *usb_hcd)
> priv_write_copy(priv, (u32 *)&ptd, usb_hcd->regs +
> atl_regs, sizeof(ptd));
>
>+ priv->atl_queued++;
>+ if (priv->atl_queued == 2)
>+ isp1760_writel(INTERRUPT_ENABLE_SOT_MASK,
>+ usb_hcd->regs + HC_INTERRUPT_ENABLE);
>+
> buffstatus = isp1760_readl(usb_hcd->regs +
> HC_BUFFER_STATUS_REG);
> buffstatus |= ATL_BUFFER;
>@@ -1191,6 +1198,9 @@ static void do_atl_int(struct usb_hcd *usb_hcd)
> skip_map = isp1760_readl(usb_hcd->regs +
> HC_ATL_PTD_SKIPMAP_REG);
> }
>+ if (priv->atl_queued <= 1)
>+ isp1760_writel(INTERRUPT_ENABLE_MASK,
>+ usb_hcd->regs + HC_INTERRUPT_ENABLE);
> }
>
> static void do_intl_int(struct usb_hcd *usb_hcd)
>@@ -1770,7 +1780,7 @@ static irqreturn_t isp1760_irq(struct usb_hcd *usb_hcd)
> goto leave;
>
> isp1760_writel(imask, usb_hcd->regs + HC_INTERRUPT_REG);
>- if (imask & HC_ATL_INT)
>+ if (imask & (HC_ATL_INT | HC_SOT_INT))
> do_atl_int(usb_hcd);
>
> if (imask & HC_INTL_INT)
>diff --git a/drivers/usb/host/isp1760-hcd.h b/drivers/usb/host/isp1760-hcd.h
>index 6931ef5..612bce5 100644
>--- a/drivers/usb/host/isp1760-hcd.h
>+++ b/drivers/usb/host/isp1760-hcd.h
>@@ -69,6 +69,7 @@ void deinit_kmem_cache(void);
>
> #define HC_INTERRUPT_ENABLE 0x314
> #define INTERRUPT_ENABLE_MASK (HC_INTL_INT | HC_ATL_INT | HC_EOT_INT)
>+#define INTERRUPT_ENABLE_SOT_MASK (HC_INTL_INT | HC_SOT_INT | HC_EOT_INT)
>
> #define HC_ISO_INT (1 << 9)
> #define HC_ATL_INT (1 << 8)
>--
>1.7.3.2
Sebastian
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