[PATCH RESEND] usb: dwc2: avoid leaking DMA channels on disconnection

[PATCH RESEND] usb: dwc2: avoid leaking DMA channels on disconnection

[Vincent Palatin]

When the HCD is disconnected, the DMA transfers still in-flight were cleaned-up
but the count of available DMA channels (e.g. available_host_channels) was not
reset.
The pool of DMA channels can be depleted when doing unclean
disconnection of USB peripherals, and reaches the point where no
transfer was possible until the next reboot/reload of the driver.

Tested by putting a programmable USB mux on the port and randomly
plugging/unpluging a USB HUB with USB mass-storage key, USB-audio and
USB-ethernet dongle connected to its downstream ports, and also doing the
disconnection early while the devices are still enumerating to get more URBs
in-flight.
After the patch, the devices are still enumerating after thousands of cycles,
while the port was totally dead before.

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
---
I'm re-sending it, it seems the previous email did not show up.

 drivers/usb/dwc2/hcd.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index c78c874..559b55e 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -257,6 +257,14 @@ static void dwc2_hcd_cleanup_channels(struct dwc2_hsotg *hsotg)
 		 */
 		channel->qh = NULL;
 	}
+	/* All channels have been freed, mark them available */
+	if (hsotg->core_params->uframe_sched > 0) {
+		hsotg->available_host_channels =
+			hsotg->core_params->host_channels;
+	} else {
+		hsotg->non_periodic_channels = 0;
+		hsotg->periodic_channels = 0;
+	}
 }
 
 /**
-- 
2.2.0.rc0.207.ga3a616c

Re: [PATCH RESEND] usb: dwc2: avoid leaking DMA channels on disconnection

[Yunzhi Li]

Hi
> When the HCD is disconnected, the DMA transfers still in-flight were cleaned-up
> but the count of available DMA channels (e.g. available_host_channels) was not
> reset.
> The pool of DMA channels can be depleted when doing unclean
> disconnection of USB peripherals, and reaches the point where no
> transfer was possible until the next reboot/reload of the driver.
>
> Tested by putting a programmable USB mux on the port and randomly
> plugging/unpluging a USB HUB with USB mass-storage key, USB-audio and
> USB-ethernet dongle connected to its downstream ports, and also doing the
> disconnection early while the devices are still enumerating to get more URBs
> in-flight.
> After the patch, the devices are still enumerating after thousands of cycles,
> while the port was totally dead before.
>
> Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
> ---
> I'm re-sending it, it seems the previous email did not show up.
>
>   drivers/usb/dwc2/hcd.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
> index c78c874..559b55e 100644
> --- a/drivers/usb/dwc2/hcd.c
> +++ b/drivers/usb/dwc2/hcd.c
> @@ -257,6 +257,14 @@ static void dwc2_hcd_cleanup_channels(struct dwc2_hsotg *hsotg)
>   		 */
>   		channel->qh = NULL;
>   	}
> +	/* All channels have been freed, mark them available */
> +	if (hsotg->core_params->uframe_sched > 0) {
> +		hsotg->available_host_channels =
> +			hsotg->core_params->host_channels;
> +	} else {
> +		hsotg->non_periodic_channels = 0;
> +		hsotg->periodic_channels = 0;
> +	}
>   }
>   
>   /**

I have reviewed this patch. Obviously,it makes sense.

Reviewed-by: Yunzhi Li <lyz@rock-chips.com>

Re: [PATCH RESEND] usb: dwc2: avoid leaking DMA channels on disconnection

[John Youn]

On 3/16/2015 2:50 AM, Yunzhi Li wrote:
> Hi
>> When the HCD is disconnected, the DMA transfers still in-flight were cleaned-up
>> but the count of available DMA channels (e.g. available_host_channels) was not
>> reset.
>> The pool of DMA channels can be depleted when doing unclean
>> disconnection of USB peripherals, and reaches the point where no
>> transfer was possible until the next reboot/reload of the driver.
>>
>> Tested by putting a programmable USB mux on the port and randomly
>> plugging/unpluging a USB HUB with USB mass-storage key, USB-audio and
>> USB-ethernet dongle connected to its downstream ports, and also doing the
>> disconnection early while the devices are still enumerating to get more URBs
>> in-flight.
>> After the patch, the devices are still enumerating after thousands of cycles,
>> while the port was totally dead before.
>>
>> Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
>> ---
>> I'm re-sending it, it seems the previous email did not show up.
>>
>>   drivers/usb/dwc2/hcd.c | 8 ++++++++
>>   1 file changed, 8 insertions(+)
>>
>> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
>> index c78c874..559b55e 100644
>> --- a/drivers/usb/dwc2/hcd.c
>> +++ b/drivers/usb/dwc2/hcd.c
>> @@ -257,6 +257,14 @@ static void dwc2_hcd_cleanup_channels(struct dwc2_hsotg *hsotg)
>>   		 */
>>   		channel->qh = NULL;
>>   	}
>> +	/* All channels have been freed, mark them available */
>> +	if (hsotg->core_params->uframe_sched > 0) {
>> +		hsotg->available_host_channels =
>> +			hsotg->core_params->host_channels;
>> +	} else {
>> +		hsotg->non_periodic_channels = 0;
>> +		hsotg->periodic_channels = 0;
>> +	}
>>   }
>>   
>>   /**
> 
> I have reviewed this patch. Obviously,it makes sense.
> 
> Reviewed-by: Yunzhi Li <lyz@rock-chips.com>


Acked-by: John Youn <johnyoun@synopsys.com>