Re: [PATCH v2] usb: host: Implement workaround for Erratum A-009611

From: Felipe Balbi
Date: Fri Dec 08 2017 - 05:54:35 EST



Hi,

Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> writes:
> On Fri, Dec 08, 2017 at 05:49:41PM +0800, yinbo.zhu@xxxxxxx wrote:
>> From: "yinbo.zhu" <yinbo.zhu@xxxxxxx>
>>
>> Description: This is a occasional problem where the software
>
> No need for a "Description:" word. That's just assumed here, right?
>
>> issues an End Transfer command while a USB transfer is in progress,
>> resulting in the TxFIFO being flushed when the lower layer is waiting
>> for data,causing the super speed (SS) transmit to get blocked.
>> If the End Transfer command is issued on an IN endpoint to
>> flush out the pending transfers when the same IN endpoint
>> is doing transfers on the USB, then depending upon the timing
>> of the End Transfer (and the resulting internal FIFO flush),the
>> lower layer (U3PTL/U3MAC) could get stuck waiting for data
>> indefinitely. This blocks the transmission path on the SS, and no
>> DP/ACK/ERDY/DEVNOTIF packets can be sent from the device.
>> Impact: If this issue happens and the transmission gets blocked,
>> then the USB host aborts and resets/re-enumerates the device.
>> This unblocks the transmitt engine and the device functions normally.
>>
>> Workaround: Software must wait for all existing TRBs to complete before
>> issuing End transfer command.
>>
>> Configs Affected:
>> LS1088-48A-R1.0, LS2081A-R1.1, LS2088-48A-R1.0, LS2088-48A-R1.1,
>> LX2160-2120-2080A-R1.
>
> What are these Configs? That doesn't seem to match up with anything
> that is in the kernel tree that I can see.
>
>>
>> Signed-off-by: yinbo.zhu <yinbo.zhu@xxxxxxx>
>> ---
>> drivers/usb/dwc3/core.c | 3 +++
>> drivers/usb/dwc3/core.h | 3 +++
>> drivers/usb/dwc3/host.c | 3 +++
>> drivers/usb/host/xhci-plat.c | 4 ++++
>> drivers/usb/host/xhci.c | 24 ++++++++++++++++++------
>> drivers/usb/host/xhci.h | 1 +
>> 6 files changed, 32 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index 5cb3f6795b0b..071e7cea8cbb 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -1106,6 +1106,9 @@ static void dwc3_get_properties(struct dwc3 *dwc)
>>
>> dwc->quirk_reverse_in_out = device_property_read_bool(dev,
>> "snps,quirk_reverse_in_out");

This was generated on vendor tree. This quirk doesn't exist in
dwc3. Also, update your tree and review MAINTAINERS file. It has been
almost 2 years since I left TI :-)

--
balbi

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