[PATCH 0/4] usb: dwc3: Fixes and code cleanup

[PATCH 0/4] usb: dwc3: Fixes and code cleanup

[Amit Virdi]

The first two patches are bug fixes in TRB preparation when scatter gather is
used. The next two patches are basically trivial and part of code cleanup.

The patches are rebased on Balbi's testing/next branch.

Amit Virdi (4):
  usb: dwc3: gadget: Fix TRB preparation during SG
  usb: dwc3: gadget: Stop TRB preparation after limit is reached
  usb: dwc3: gadget: Remove redundant check
  usb: dwc3: Remove current_trb as it is unused

 drivers/usb/dwc3/core.h   | 3 ---
 drivers/usb/dwc3/gadget.c | 9 ++++-----
 2 files changed, 4 insertions(+), 8 deletions(-)

-- 
1.8.0

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[PATCH 1/4] usb: dwc3: gadget: Fix TRB preparation during SG

[Amit Virdi]

When scatter gather is used, multiple TRBs are prepared from one DWC3 request.
Hence, we must set the 'last' flag when the SG is last as well as the TRB is
last. The current implementation uses list_is_last to check if the dwc3_request
is the last request in the request_list.

This doesn't work when SG is used. This is because, when it is the last request,
the first TRB preparation (in dwc3_prepare_one_trb) modifies the dwc3_request
list's next and prev pointers while moving the URB to req_queued.

Hence, list_is_last always return false no matter what. The correct way is not
to access the modified pointers of dwc3_request but to use list_empty macro
instead.

Fixes: e5ba5ec833aa4a76980b512d6a6779643516b850 ("usb: dwc3: gadget: fix scatter
gather implementation"

Signed-off-by: Amit Virdi <amit.virdi@st.com>
---
 drivers/usb/dwc3/gadget.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index f03b136ecfce..0eec2e917994 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -882,8 +882,7 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
 
 				if (i == (request->num_mapped_sgs - 1) ||
 						sg_is_last(s)) {
-					if (list_is_last(&req->list,
-							&dep->request_list))
+					if (list_empty(&dep->request_list))
 						last_one = true;
 					chain = false;
 				}
-- 
1.8.0

Re: [PATCH 1/4] usb: dwc3: gadget: Fix TRB preparation during SG

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 1899 bytes --]

On Fri, Dec 19, 2014 at 12:40:15PM +0530, Amit Virdi wrote:
> When scatter gather is used, multiple TRBs are prepared from one DWC3 request.
> Hence, we must set the 'last' flag when the SG is last as well as the TRB is
> last. The current implementation uses list_is_last to check if the dwc3_request
> is the last request in the request_list.
> 
> This doesn't work when SG is used. This is because, when it is the last request,
> the first TRB preparation (in dwc3_prepare_one_trb) modifies the dwc3_request
> list's next and prev pointers while moving the URB to req_queued.
> 
> Hence, list_is_last always return false no matter what. The correct way is not
> to access the modified pointers of dwc3_request but to use list_empty macro
> instead.
> 
> Fixes: e5ba5ec833aa4a76980b512d6a6779643516b850 ("usb: dwc3: gadget: fix scatter
> gather implementation"
> 
> Signed-off-by: Amit Virdi <amit.virdi@st.com>

you need to Cc stable here and make sure you point out which kernel
versions this should be backported to. Looks like this sould be:

Cc: <stable@vger.kernel.org> # v3.9+

Also, how have you tested this ? I need a test case to make sure it
fails here and this patch really fixes the problem.

> ---
>  drivers/usb/dwc3/gadget.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index f03b136ecfce..0eec2e917994 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -882,8 +882,7 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
>  
>  				if (i == (request->num_mapped_sgs - 1) ||
>  						sg_is_last(s)) {
> -					if (list_is_last(&req->list,
> -							&dep->request_list))
> +					if (list_empty(&dep->request_list))
>  						last_one = true;
>  					chain = false;
>  				}
> -- 
> 1.8.0
> 

-- 
balbi

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Re: [PATCH 1/4] usb: dwc3: gadget: Fix TRB preparation during SG

[Amit Virdi]

On Mon, Dec 22, 2014 at 9:34 PM, Felipe Balbi <balbi@ti.com> wrote:
> On Fri, Dec 19, 2014 at 12:40:15PM +0530, Amit Virdi wrote:
>> When scatter gather is used, multiple TRBs are prepared from one DWC3 request.
>> Hence, we must set the 'last' flag when the SG is last as well as the TRB is
>> last. The current implementation uses list_is_last to check if the dwc3_request
>> is the last request in the request_list.
>>
>> This doesn't work when SG is used. This is because, when it is the last request,
>> the first TRB preparation (in dwc3_prepare_one_trb) modifies the dwc3_request
>> list's next and prev pointers while moving the URB to req_queued.
>>
>> Hence, list_is_last always return false no matter what. The correct way is not
>> to access the modified pointers of dwc3_request but to use list_empty macro
>> instead.
>>
>> Fixes: e5ba5ec833aa4a76980b512d6a6779643516b850 ("usb: dwc3: gadget: fix scatter
>> gather implementation"
>>
>> Signed-off-by: Amit Virdi <amit.virdi@st.com>
>
> you need to Cc stable here and make sure you point out which kernel
> versions this should be backported to. Looks like this sould be:
>
> Cc: <stable@vger.kernel.org> # v3.9+

Okay. I checked the git log. The commit ("usb: dwc3: gadget: fix
scatter gather implementation") was introduced in v3.8-rc5, hence
v3.8, so I need to

Cc: <stable@vger.kernel.org> # v3.8+

>
> Also, how have you tested this ? I need a test case to make sure it
> fails here and this patch really fixes the problem.
>

This bug can be easily reproduced/tested if the gadget driver submits
a urb having number of sg entries mapped to DMA more than 1 on bulk
endpoint. Following is the log snippet once this bug is reproduced:
----
dwc3 dwc3.0: ep2in-bulk: Transfer Not Ready
dwc3 dwc3.0: queing request 24cc5780 to ep2in-bulk length 960002
dwc3 dwc3.0: ep2in-bulk: req 24cc5780 dma 24eb6400 length 2 chain
dwc3 dwc3.0: ep2in-bulk: req 24cc5780 dma 25901800 length 960000
dwc3 dwc3.0: queing request 24cc5000 to ep2in-bulk length 960002
dwc3 dwc3.0: ep2in-bulk: Transfer Not Ready
dwc3 dwc3.0: queing request 24cc5900 to ep2in-bulk length 960002
-----

Without this fix, the hardware never generates "Transfer Complete"
event for the corresponding EP and goes into an unknown state.

Re: [PATCH 1/4] usb: dwc3: gadget: Fix TRB preparation during SG

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 3476 bytes --]

Hi,

On Sat, Dec 27, 2014 at 12:39:23PM +0530, Amit Virdi wrote:
> On Mon, Dec 22, 2014 at 9:34 PM, Felipe Balbi <balbi@ti.com> wrote:
> > On Fri, Dec 19, 2014 at 12:40:15PM +0530, Amit Virdi wrote:
> >> When scatter gather is used, multiple TRBs are prepared from one DWC3 request.
> >> Hence, we must set the 'last' flag when the SG is last as well as the TRB is
> >> last. The current implementation uses list_is_last to check if the dwc3_request
> >> is the last request in the request_list.
> >>
> >> This doesn't work when SG is used. This is because, when it is the last request,
> >> the first TRB preparation (in dwc3_prepare_one_trb) modifies the dwc3_request
> >> list's next and prev pointers while moving the URB to req_queued.
> >>
> >> Hence, list_is_last always return false no matter what. The correct way is not
> >> to access the modified pointers of dwc3_request but to use list_empty macro
> >> instead.
> >>
> >> Fixes: e5ba5ec833aa4a76980b512d6a6779643516b850 ("usb: dwc3: gadget: fix scatter
> >> gather implementation"
> >>
> >> Signed-off-by: Amit Virdi <amit.virdi@st.com>
> >
> > you need to Cc stable here and make sure you point out which kernel
> > versions this should be backported to. Looks like this sould be:
> >
> > Cc: <stable@vger.kernel.org> # v3.9+
> 
> Okay. I checked the git log. The commit ("usb: dwc3: gadget: fix
> scatter gather implementation") was introduced in v3.8-rc5, hence
> v3.8, so I need to
> 
> Cc: <stable@vger.kernel.org> # v3.8+

hehe, many folks get confused by this. New features will never get
merged upstream during the -rc cycle. -rc5 is when I applied it to my
tree so it could be merged on the following merge window, which was
v3.9.

> > Also, how have you tested this ? I need a test case to make sure it
> > fails here and this patch really fixes the problem.
> >
> 
> This bug can be easily reproduced/tested if the gadget driver submits
> a urb having number of sg entries mapped to DMA more than 1 on bulk

which gadget driver does this ?

> endpoint. Following is the log snippet once this bug is reproduced:
> ----
> dwc3 dwc3.0: ep2in-bulk: Transfer Not Ready
> dwc3 dwc3.0: queing request 24cc5780 to ep2in-bulk length 960002
> dwc3 dwc3.0: ep2in-bulk: req 24cc5780 dma 24eb6400 length 2 chain
> dwc3 dwc3.0: ep2in-bulk: req 24cc5780 dma 25901800 length 960000
> dwc3 dwc3.0: queing request 24cc5000 to ep2in-bulk length 960002
> dwc3 dwc3.0: ep2in-bulk: Transfer Not Ready
> dwc3 dwc3.0: queing request 24cc5900 to ep2in-bulk length 960002
> -----
> 
> Without this fix, the hardware never generates "Transfer Complete"
> event for the corresponding EP and goes into an unknown state.

whiuch kernel are you using to develop this ? Most of these messages
don't exist anymore with v3.19-rc because I have converted them into
tracepoints, considering you're showing me logs with these messages,
this tells me that you're sending me a patch developed/tested against a
kernel older than v3.18. I need to see full bootup logs, a register dump
(/sys/kernel/debug/*dwc3*/regdump) and a much larger debugging log from
dwc3 in order to accept patches from you. Sorry, but I cannot take
patches which were not tested against, at a minimum, the latest major
release.

It would be much better if you developed/tested against v3.19-rc1,
considering we have 40 different patches which were merged since v3.18
was tagged.

-- 
balbi

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Re: [PATCH 1/4] usb: dwc3: gadget: Fix TRB preparation during SG

[Amit Virdi]

On Sat, Dec 27, 2014 at 11:14 PM, Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org> wrote:
> Hi,
>
> On Sat, Dec 27, 2014 at 12:39:23PM +0530, Amit Virdi wrote:
>> On Mon, Dec 22, 2014 at 9:34 PM, Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org> wrote:
>> > On Fri, Dec 19, 2014 at 12:40:15PM +0530, Amit Virdi wrote:
>> >> When scatter gather is used, multiple TRBs are prepared from one DWC3 request.
>> >> Hence, we must set the 'last' flag when the SG is last as well as the TRB is
>> >> last. The current implementation uses list_is_last to check if the dwc3_request
>> >> is the last request in the request_list.
>> >>
>> >> This doesn't work when SG is used. This is because, when it is the last request,
>> >> the first TRB preparation (in dwc3_prepare_one_trb) modifies the dwc3_request
>> >> list's next and prev pointers while moving the URB to req_queued.
>> >>
>> >> Hence, list_is_last always return false no matter what. The correct way is not
>> >> to access the modified pointers of dwc3_request but to use list_empty macro
>> >> instead.
>> >>
>> >> Fixes: e5ba5ec833aa4a76980b512d6a6779643516b850 ("usb: dwc3: gadget: fix scatter
>> >> gather implementation"
>> >>
>> >> Signed-off-by: Amit Virdi <amit.virdi-qxv4g6HH51o@public.gmane.org>
>> >
>> > you need to Cc stable here and make sure you point out which kernel
>> > versions this should be backported to. Looks like this sould be:
>> >
>> > Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org> # v3.9+
>>
>> Okay. I checked the git log. The commit ("usb: dwc3: gadget: fix
>> scatter gather implementation") was introduced in v3.8-rc5, hence
>> v3.8, so I need to
>>
>> Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org> # v3.8+
>
> hehe, many folks get confused by this. New features will never get
> merged upstream during the -rc cycle. -rc5 is when I applied it to my
> tree so it could be merged on the following merge window, which was
> v3.9.
>

Got it, thanks!

>> > Also, how have you tested this ? I need a test case to make sure it
>> > fails here and this patch really fixes the problem.
>> >
>>
>> This bug can be easily reproduced/tested if the gadget driver submits
>> a urb having number of sg entries mapped to DMA more than 1 on bulk
>
> which gadget driver does this ?
>

I discovered the bug fixed in this patch and the other [2/4], when I
was using our customized uvc webcam gadget.

>> endpoint. Following is the log snippet once this bug is reproduced:
>> ----
>> dwc3 dwc3.0: ep2in-bulk: Transfer Not Ready
>> dwc3 dwc3.0: queing request 24cc5780 to ep2in-bulk length 960002
>> dwc3 dwc3.0: ep2in-bulk: req 24cc5780 dma 24eb6400 length 2 chain
>> dwc3 dwc3.0: ep2in-bulk: req 24cc5780 dma 25901800 length 960000
>> dwc3 dwc3.0: queing request 24cc5000 to ep2in-bulk length 960002
>> dwc3 dwc3.0: ep2in-bulk: Transfer Not Ready
>> dwc3 dwc3.0: queing request 24cc5900 to ep2in-bulk length 960002
>> -----
>>
>> Without this fix, the hardware never generates "Transfer Complete"
>> event for the corresponding EP and goes into an unknown state.
>
> whiuch kernel are you using to develop this ? Most of these messages
> don't exist anymore with v3.19-rc because I have converted them into
> tracepoints, considering you're showing me logs with these messages,
> this tells me that you're sending me a patch developed/tested against a
> kernel older than v3.18. I need to see full bootup logs, a register dump
> (/sys/kernel/debug/*dwc3*/regdump) and a much larger debugging log from
> dwc3 in order to accept patches from you. Sorry, but I cannot take
> patches which were not tested against, at a minimum, the latest major
> release.
>
> It would be much better if you developed/tested against v3.19-rc1,
> considering we have 40 different patches which were merged since v3.18
> was tagged.
>

Your comments for this patch and the other are similar. So, I'm
quoting your comments from here to the other thread (of patch 2/4) and
replying there to avoid any duplicacy.
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[PATCH 3/4] usb: dwc3: gadget: Remove redundant check

[Amit Virdi]

dwc3_gadget_init_hw_endpoints calls dwc3_alloc_trb_pool only if epnum is not
equal to 0 or 1. Hence, rechecking it in the called function is redundant.

Signed-off-by: Amit Virdi <amit.virdi@st.com>
---
 drivers/usb/dwc3/gadget.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 8f65ab3a3b92..8c2e2fbe6f39 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -352,9 +352,6 @@ static int dwc3_alloc_trb_pool(struct dwc3_ep *dep)
 	if (dep->trb_pool)
 		return 0;
 
-	if (dep->number == 0 || dep->number == 1)
-		return 0;
-
 	dep->trb_pool = dma_alloc_coherent(dwc->dev,
 			sizeof(struct dwc3_trb) * DWC3_TRB_NUM,
 			&dep->trb_pool_dma, GFP_KERNEL);
-- 
1.8.0

[PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Amit Virdi]

When SG is used, there are two loops iterating to prepare TRBs:
 - Outer loop over the request_list
 - Inner loop over the SG list

The driver must stop preparing TRBs when the max TRBs have been prepared. The
code was missing break to get out of the outer loop.

Signed-off-by: Amit Virdi <amit.virdi-qxv4g6HH51o@public.gmane.org>
---
 drivers/usb/dwc3/gadget.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 0eec2e917994..8f65ab3a3b92 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -900,6 +900,9 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
 				if (last_one)
 					break;
 			}
+
+			if (last_one)
+				break;
 		} else {
 			dma = req->request.dma;
 			length = req->request.length;
-- 
1.8.0

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Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 1144 bytes --]

On Fri, Dec 19, 2014 at 12:40:16PM +0530, Amit Virdi wrote:
> When SG is used, there are two loops iterating to prepare TRBs:
>  - Outer loop over the request_list
>  - Inner loop over the SG list
> 
> The driver must stop preparing TRBs when the max TRBs have been prepared. The
> code was missing break to get out of the outer loop.
> 
> Signed-off-by: Amit Virdi <amit.virdi@st.com>

which bug is this fixing ? Which kernels are affected ? This need to be
backported to which kernel ? Which commit introduced this bug ? How can
I validate this to be a valid fix ?

> ---
>  drivers/usb/dwc3/gadget.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 0eec2e917994..8f65ab3a3b92 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -900,6 +900,9 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
>  				if (last_one)
>  					break;
>  			}
> +
> +			if (last_one)
> +				break;
>  		} else {
>  			dma = req->request.dma;
>  			length = req->request.length;
> -- 
> 1.8.0
> 

-- 
balbi

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Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Amit Virdi]

On Mon, Dec 22, 2014 at 9:36 PM, Felipe Balbi <balbi@ti.com> wrote:
> On Fri, Dec 19, 2014 at 12:40:16PM +0530, Amit Virdi wrote:
>> When SG is used, there are two loops iterating to prepare TRBs:
>>  - Outer loop over the request_list
>>  - Inner loop over the SG list
>>
>> The driver must stop preparing TRBs when the max TRBs have been prepared. The
>> code was missing break to get out of the outer loop.
>>
>> Signed-off-by: Amit Virdi <amit.virdi@st.com>
>
> which bug is this fixing ? Which kernels are affected ? This need to be
> backported to which kernel ? Which commit introduced this bug ? How can
> I validate this to be a valid fix ?
>

Problem description:
DWC3 gadget sets up a pool of 32 TRBs for each EP during
initialization. This means, the max TRBs that can be submitted for an
EP is fixed to 32. Since the request queue for an EP is a linked list,
any number of requests can be queued to it by the gadget layer.
However, the dwc3 driver must not submit TRBs more than the pool it
has created for. This limit wasn't respected when SG was used
resulting in submitting more than the max TRBs, eventually leading to
non-transfer of the TRBs submitted over the max limit.

Commit that introduced this bug:
This bug is present from the day support for sg list was added to dwc3
gadget., i.e. since commit eeb720fb21d61dfc3aac780e721150998ef603af
("usb: dwc3: gadget: add support for SG lists") - kernel version
v3.2-rc7, hence v3.2

Kernels affected:
It is best to backport this fix to kernel v3.8+ as there were many
enhancements/bug fixes from v3.2..v3.8

Generic setup to reproduce/test this fix:
This bug is reproduced whenever the number of TRBs that need to be
submitted to the hardware from the software queue (request_list)
becomes more than 32 on bulk endpoint. eg. if num_mapped_sgs is 2 and
the request_list has 17 entries (hence, 34 potential TRBs), the
scenario is reproduced.

My setup details:
For reproducing and testing the patches [1/4 and 2/4], I used an
inhouse developed user space application that run on device side. This
user space application interacts with the customized uvc webcam gadget
to submit the video data to the DWC3 driver. The host side was running
standard webcam application (cheese).

Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 2851 bytes --]

Hi,

On Sat, Dec 27, 2014 at 01:24:03PM +0530, Amit Virdi wrote:
> On Mon, Dec 22, 2014 at 9:36 PM, Felipe Balbi <balbi@ti.com> wrote:
> > On Fri, Dec 19, 2014 at 12:40:16PM +0530, Amit Virdi wrote:
> >> When SG is used, there are two loops iterating to prepare TRBs:
> >>  - Outer loop over the request_list
> >>  - Inner loop over the SG list
> >>
> >> The driver must stop preparing TRBs when the max TRBs have been prepared. The
> >> code was missing break to get out of the outer loop.
> >>
> >> Signed-off-by: Amit Virdi <amit.virdi@st.com>
> >
> > which bug is this fixing ? Which kernels are affected ? This need to be
> > backported to which kernel ? Which commit introduced this bug ? How can
> > I validate this to be a valid fix ?
> >
> 
> Problem description:
> DWC3 gadget sets up a pool of 32 TRBs for each EP during
> initialization. This means, the max TRBs that can be submitted for an
> EP is fixed to 32. Since the request queue for an EP is a linked list,
> any number of requests can be queued to it by the gadget layer.
> However, the dwc3 driver must not submit TRBs more than the pool it
> has created for. This limit wasn't respected when SG was used
> resulting in submitting more than the max TRBs, eventually leading to
> non-transfer of the TRBs submitted over the max limit.

this would become a much, much better commit log than the one you
provided. It's a much more verbose description of the issue.

> Commit that introduced this bug:
> This bug is present from the day support for sg list was added to dwc3
> gadget., i.e. since commit eeb720fb21d61dfc3aac780e721150998ef603af
> ("usb: dwc3: gadget: add support for SG lists") - kernel version
> v3.2-rc7, hence v3.2
> 
> Kernels affected:
> It is best to backport this fix to kernel v3.8+ as there were many
> enhancements/bug fixes from v3.2..v3.8
> 
> Generic setup to reproduce/test this fix:
> This bug is reproduced whenever the number of TRBs that need to be
> submitted to the hardware from the software queue (request_list)
> becomes more than 32 on bulk endpoint. eg. if num_mapped_sgs is 2 and
> the request_list has 17 entries (hence, 34 potential TRBs), the
> scenario is reproduced.
> 
> My setup details:
> For reproducing and testing the patches [1/4 and 2/4], I used an
> inhouse developed user space application that run on device side. This
> user space application interacts with the customized uvc webcam gadget
> to submit the video data to the DWC3 driver. The host side was running
> standard webcam application (cheese).

oh, so this is something I can't easily reproduce myself. Then I'll need
full boot logs, register dump and full trace output of dwc3 running and
exhibiting the problem. Also, make sure you use either v3.18 or v3.19rc1
to validate your changes.

-- 
balbi

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Amit Virdi]

On Sat, Dec 27, 2014 at 11:16 PM, Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org> wrote:
> Hi,
>
> On Sat, Dec 27, 2014 at 01:24:03PM +0530, Amit Virdi wrote:
>> On Mon, Dec 22, 2014 at 9:36 PM, Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org> wrote:
>> > On Fri, Dec 19, 2014 at 12:40:16PM +0530, Amit Virdi wrote:
>> >> When SG is used, there are two loops iterating to prepare TRBs:
>> >>  - Outer loop over the request_list
>> >>  - Inner loop over the SG list
>> >>
>> >> The driver must stop preparing TRBs when the max TRBs have been prepared. The
>> >> code was missing break to get out of the outer loop.
>> >>
>> >> Signed-off-by: Amit Virdi <amit.virdi-qxv4g6HH51o@public.gmane.org>
>> >
>> > which bug is this fixing ? Which kernels are affected ? This need to be
>> > backported to which kernel ? Which commit introduced this bug ? How can
>> > I validate this to be a valid fix ?
>> >
>>
>> Problem description:
>> DWC3 gadget sets up a pool of 32 TRBs for each EP during
>> initialization. This means, the max TRBs that can be submitted for an
>> EP is fixed to 32. Since the request queue for an EP is a linked list,
>> any number of requests can be queued to it by the gadget layer.
>> However, the dwc3 driver must not submit TRBs more than the pool it
>> has created for. This limit wasn't respected when SG was used
>> resulting in submitting more than the max TRBs, eventually leading to
>> non-transfer of the TRBs submitted over the max limit.
>
> this would become a much, much better commit log than the one you
> provided. It's a much more verbose description of the issue.
>

Okay, I'll edit the commit message.

>> Commit that introduced this bug:
>> This bug is present from the day support for sg list was added to dwc3
>> gadget., i.e. since commit eeb720fb21d61dfc3aac780e721150998ef603af
>> ("usb: dwc3: gadget: add support for SG lists") - kernel version
>> v3.2-rc7, hence v3.2
>>
>> Kernels affected:
>> It is best to backport this fix to kernel v3.8+ as there were many
>> enhancements/bug fixes from v3.2..v3.8
>>
>> Generic setup to reproduce/test this fix:
>> This bug is reproduced whenever the number of TRBs that need to be
>> submitted to the hardware from the software queue (request_list)
>> becomes more than 32 on bulk endpoint. eg. if num_mapped_sgs is 2 and
>> the request_list has 17 entries (hence, 34 potential TRBs), the
>> scenario is reproduced.
>>
>> My setup details:
>> For reproducing and testing the patches [1/4 and 2/4], I used an
>> inhouse developed user space application that run on device side. This
>> user space application interacts with the customized uvc webcam gadget
>> to submit the video data to the DWC3 driver. The host side was running
>> standard webcam application (cheese).
>
> oh, so this is something I can't easily reproduce myself. Then I'll need
> full boot logs, register dump and full trace output of dwc3 running and
> exhibiting the problem. Also, make sure you use either v3.18 or v3.19rc1
> to validate your changes.
>

[Quoting you from the thread of patch 1/4]

>> endpoint. Following is the log snippet once this bug is reproduced:
>> ----
>> dwc3 dwc3.0: ep2in-bulk: Transfer Not Ready
>> dwc3 dwc3.0: queing request 24cc5780 to ep2in-bulk length 960002
>> dwc3 dwc3.0: ep2in-bulk: req 24cc5780 dma 24eb6400 length 2 chain
>> dwc3 dwc3.0: ep2in-bulk: req 24cc5780 dma 25901800 length 960000
>> dwc3 dwc3.0: queing request 24cc5000 to ep2in-bulk length 960002
>> dwc3 dwc3.0: ep2in-bulk: Transfer Not Ready
>> dwc3 dwc3.0: queing request 24cc5900 to ep2in-bulk length 960002
>> -----
>>
>> Without this fix, the hardware never generates "Transfer Complete"
>> event for the corresponding EP and goes into an unknown state.
>
> whiuch kernel are you using to develop this ? Most of these messages
> don't exist anymore with v3.19-rc because I have converted them into
> tracepoints, considering you're showing me logs with these messages,
> this tells me that you're sending me a patch developed/tested against a
> kernel older than v3.18. I need to see full bootup logs, a register dump
> (/sys/kernel/debug/*dwc3*/regdump) and a much larger debugging log from
> dwc3 in order to accept patches from you. Sorry, but I cannot take
> patches which were not tested against, at a minimum, the latest major
> release.
>

Yes you're right that both the fixes [1/4] and [2/4] have only been
build tested with the latest kernel. I should have mentioned this
information in the commit message or the cover-letter itself.

The only reason why I have not been able to test these fixes on the
latest is because the customized webcam gadget is not ported on the
latest kernel. There have been a lot of changes in the video framework
lately and that is not my area of expertise. So porting the customized
webcam gadget to latest kernel and testing these fixes is not feasible
for me.

Having said all this, the fact remains that these are bugs in the dwc3
driver from kernel v3.9 onwards. The log messages clearly depict this.
These bugs are obviously present till date.

I ask you to give a more deeper thought on the whole situation and not
undermine the importance of code review.
 - [Patch 2/4] fixes a bug that could have been found in the code review.
 - [Patch 1/4] fixes a bug which was very very subtle but a deeper
code review can certainly boost the confidence about the change made.
list_is_last won't work when SG is used because, for the last request
in the request_list, the TRB for the first sg entry modifies the
list's next and prev pointers while moving the URB to req_queued.

I can certainly provide the dwc3 specific kernel bootup logs, full
regdump and any loglevel you want me to, if that helps
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Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 6765 bytes --]

Hi,

On Mon, Dec 29, 2014 at 12:05:57PM +0530, Amit Virdi wrote:
> >> >> When SG is used, there are two loops iterating to prepare TRBs:
> >> >>  - Outer loop over the request_list
> >> >>  - Inner loop over the SG list
> >> >>
> >> >> The driver must stop preparing TRBs when the max TRBs have been prepared. The
> >> >> code was missing break to get out of the outer loop.
> >> >>
> >> >> Signed-off-by: Amit Virdi <amit.virdi@st.com>
> >> >
> >> > which bug is this fixing ? Which kernels are affected ? This need to be
> >> > backported to which kernel ? Which commit introduced this bug ? How can
> >> > I validate this to be a valid fix ?
> >> >
> >>
> >> Problem description:
> >> DWC3 gadget sets up a pool of 32 TRBs for each EP during
> >> initialization. This means, the max TRBs that can be submitted for an
> >> EP is fixed to 32. Since the request queue for an EP is a linked list,
> >> any number of requests can be queued to it by the gadget layer.
> >> However, the dwc3 driver must not submit TRBs more than the pool it
> >> has created for. This limit wasn't respected when SG was used
> >> resulting in submitting more than the max TRBs, eventually leading to
> >> non-transfer of the TRBs submitted over the max limit.
> >
> > this would become a much, much better commit log than the one you
> > provided. It's a much more verbose description of the issue.
> 
> Okay, I'll edit the commit message.

thanks

> >> Commit that introduced this bug:
> >> This bug is present from the day support for sg list was added to dwc3
> >> gadget., i.e. since commit eeb720fb21d61dfc3aac780e721150998ef603af
> >> ("usb: dwc3: gadget: add support for SG lists") - kernel version
> >> v3.2-rc7, hence v3.2
> >>
> >> Kernels affected:
> >> It is best to backport this fix to kernel v3.8+ as there were many
> >> enhancements/bug fixes from v3.2..v3.8
> >>
> >> Generic setup to reproduce/test this fix:
> >> This bug is reproduced whenever the number of TRBs that need to be
> >> submitted to the hardware from the software queue (request_list)
> >> becomes more than 32 on bulk endpoint. eg. if num_mapped_sgs is 2 and
> >> the request_list has 17 entries (hence, 34 potential TRBs), the
> >> scenario is reproduced.
> >>
> >> My setup details:
> >> For reproducing and testing the patches [1/4 and 2/4], I used an
> >> inhouse developed user space application that run on device side. This
> >> user space application interacts with the customized uvc webcam gadget
> >> to submit the video data to the DWC3 driver. The host side was running
> >> standard webcam application (cheese).
> >
> > oh, so this is something I can't easily reproduce myself. Then I'll need
> > full boot logs, register dump and full trace output of dwc3 running and
> > exhibiting the problem. Also, make sure you use either v3.18 or v3.19rc1
> > to validate your changes.
> >
> 
> [Quoting you from the thread of patch 1/4]
> 
> >> endpoint. Following is the log snippet once this bug is reproduced:
> >> ----
> >> dwc3 dwc3.0: ep2in-bulk: Transfer Not Ready
> >> dwc3 dwc3.0: queing request 24cc5780 to ep2in-bulk length 960002
> >> dwc3 dwc3.0: ep2in-bulk: req 24cc5780 dma 24eb6400 length 2 chain
> >> dwc3 dwc3.0: ep2in-bulk: req 24cc5780 dma 25901800 length 960000
> >> dwc3 dwc3.0: queing request 24cc5000 to ep2in-bulk length 960002
> >> dwc3 dwc3.0: ep2in-bulk: Transfer Not Ready
> >> dwc3 dwc3.0: queing request 24cc5900 to ep2in-bulk length 960002
> >> -----
> >>
> >> Without this fix, the hardware never generates "Transfer Complete"
> >> event for the corresponding EP and goes into an unknown state.
> >
> > whiuch kernel are you using to develop this ? Most of these messages
> > don't exist anymore with v3.19-rc because I have converted them into
> > tracepoints, considering you're showing me logs with these messages,
> > this tells me that you're sending me a patch developed/tested against a
> > kernel older than v3.18. I need to see full bootup logs, a register dump
> > (/sys/kernel/debug/*dwc3*/regdump) and a much larger debugging log from
> > dwc3 in order to accept patches from you. Sorry, but I cannot take
> > patches which were not tested against, at a minimum, the latest major
> > release.
> >
> 
> Yes you're right that both the fixes [1/4] and [2/4] have only been
> build tested with the latest kernel. I should have mentioned this
> information in the commit message or the cover-letter itself.

yeah, you should've :-)

> The only reason why I have not been able to test these fixes on the
> latest is because the customized webcam gadget is not ported on the
> latest kernel. There have been a lot of changes in the video framework
> lately and that is not my area of expertise. So porting the customized
> webcam gadget to latest kernel and testing these fixes is not feasible
> for me.

right, so while I can see that both patches are very minimal and likely
to be correct, I have no way of guaranteeing that. The only thing I can
do, is run the tests which I already run (none of which exercise the
cases you found though, other I'd have found them already) to make sure
your patches don't break what's already working.

> Having said all this, the fact remains that these are bugs in the dwc3
> driver from kernel v3.9 onwards. The log messages clearly depict this.

no, it doesn't :-) your log snippet is so small that I cannot see how
the driver got to that point :-) The only thing I can see is that you
started two requests, one for 960000 bytes and another one for 2 bytes,
but I don't know how many TRBs we had available, nor do I see a Start
Transfer command, so I can't validate Start Transfer command parameters
were correct or not.

> These bugs are obviously present till date.

Right, the code is the same :-)

> I ask you to give a more deeper thought on the whole situation and not
> undermine the importance of code review.

heh

>  - [Patch 2/4] fixes a bug that could have been found in the code review.
>  - [Patch 1/4] fixes a bug which was very very subtle but a deeper
> code review can certainly boost the confidence about the change made.
> list_is_last won't work when SG is used because, for the last request
> in the request_list, the TRB for the first sg entry modifies the
> list's next and prev pointers while moving the URB to req_queued.
> 
> I can certainly provide the dwc3 specific kernel bootup logs, full
> regdump and any loglevel you want me to, if that helps

Yeah, if you can provide those, then that'll help me verifying. Full
logs from boot to failure point with VERBOSE_DEBUG enabled (considering
you're not running on anything recent).

-- 
balbi

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Amit Virdi]

>> The only reason why I have not been able to test these fixes on the
>> latest is because the customized webcam gadget is not ported on the
>> latest kernel. There have been a lot of changes in the video framework
>> lately and that is not my area of expertise. So porting the customized
>> webcam gadget to latest kernel and testing these fixes is not feasible
>> for me.
>
> right, so while I can see that both patches are very minimal and likely
> to be correct, I have no way of guaranteeing that. The only thing I can
> do, is run the tests which I already run (none of which exercise the
> cases you found though, other I'd have found them already) to make sure
> your patches don't break what's already working.
>

Okay

>> Having said all this, the fact remains that these are bugs in the dwc3
>> driver from kernel v3.9 onwards. The log messages clearly depict this.
>
> no, it doesn't :-) your log snippet is so small that I cannot see how
> the driver got to that point :-) The only thing I can see is that you
> started two requests, one for 960000 bytes and another one for 2 bytes,
> but I don't know how many TRBs we had available, nor do I see a Start
> Transfer command, so I can't validate Start Transfer command parameters
> were correct or not.
>
>> These bugs are obviously present till date.
>
> Right, the code is the same :-)
>
>> I ask you to give a more deeper thought on the whole situation and not
>> undermine the importance of code review.
>
> heh
>
>>  - [Patch 2/4] fixes a bug that could have been found in the code review.
>>  - [Patch 1/4] fixes a bug which was very very subtle but a deeper
>> code review can certainly boost the confidence about the change made.
>> list_is_last won't work when SG is used because, for the last request
>> in the request_list, the TRB for the first sg entry modifies the
>> list's next and prev pointers while moving the URB to req_queued.
>>
>> I can certainly provide the dwc3 specific kernel bootup logs, full
>> regdump and any loglevel you want me to, if that helps
>
> Yeah, if you can provide those, then that'll help me verifying. Full
> logs from boot to failure point with VERBOSE_DEBUG enabled (considering
> you're not running on anything recent).
>

Okay. I'll provide full verbose logs, along with the register dump,
when I'm back to the office next week, for the working and non-working
case, but how - as attachment or as inline?

Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 2856 bytes --]

On Tue, Dec 30, 2014 at 08:11:13PM +0530, Amit Virdi wrote:
> >> The only reason why I have not been able to test these fixes on the
> >> latest is because the customized webcam gadget is not ported on the
> >> latest kernel. There have been a lot of changes in the video framework
> >> lately and that is not my area of expertise. So porting the customized
> >> webcam gadget to latest kernel and testing these fixes is not feasible
> >> for me.
> >
> > right, so while I can see that both patches are very minimal and likely
> > to be correct, I have no way of guaranteeing that. The only thing I can
> > do, is run the tests which I already run (none of which exercise the
> > cases you found though, other I'd have found them already) to make sure
> > your patches don't break what's already working.
> >
> 
> Okay
> 
> >> Having said all this, the fact remains that these are bugs in the dwc3
> >> driver from kernel v3.9 onwards. The log messages clearly depict this.
> >
> > no, it doesn't :-) your log snippet is so small that I cannot see how
> > the driver got to that point :-) The only thing I can see is that you
> > started two requests, one for 960000 bytes and another one for 2 bytes,
> > but I don't know how many TRBs we had available, nor do I see a Start
> > Transfer command, so I can't validate Start Transfer command parameters
> > were correct or not.
> >
> >> These bugs are obviously present till date.
> >
> > Right, the code is the same :-)
> >
> >> I ask you to give a more deeper thought on the whole situation and not
> >> undermine the importance of code review.
> >
> > heh
> >
> >>  - [Patch 2/4] fixes a bug that could have been found in the code review.
> >>  - [Patch 1/4] fixes a bug which was very very subtle but a deeper
> >> code review can certainly boost the confidence about the change made.
> >> list_is_last won't work when SG is used because, for the last request
> >> in the request_list, the TRB for the first sg entry modifies the
> >> list's next and prev pointers while moving the URB to req_queued.
> >>
> >> I can certainly provide the dwc3 specific kernel bootup logs, full
> >> regdump and any loglevel you want me to, if that helps
> >
> > Yeah, if you can provide those, then that'll help me verifying. Full
> > logs from boot to failure point with VERBOSE_DEBUG enabled (considering
> > you're not running on anything recent).
> >
> 
> Okay. I'll provide full verbose logs, along with the register dump,
> when I'm back to the office next week, for the working and non-working
> case, but how - as attachment or as inline?

Either way will do but I have a feeling mailing list attachment size
will bite you, so maybe it's best to make a tarball of both logs and
send that as attachment. Compressed text will be very small.

-- 
balbi

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Amit Virdi]

[-- Attachment #1: Type: text/plain, Size: 837 bytes --]

>>>> I can certainly provide the dwc3 specific kernel bootup logs, full
>>>> regdump and any loglevel you want me to, if that helps
>>>
>>> Yeah, if you can provide those, then that'll help me verifying. Full
>>> logs from boot to failure point with VERBOSE_DEBUG enabled (considering
>>> you're not running on anything recent).
>>>
>>
>> Okay. I'll provide full verbose logs, along with the register dump,
>> when I'm back to the office next week, for the working and non-working
>> case, but how - as attachment or as inline?
>
> Either way will do but I have a feeling mailing list attachment size
> will bite you, so maybe it's best to make a tarball of both logs and
> send that as attachment. Compressed text will be very small.
>

Attached are the dwc3 verbose logs and register dump without and with 
the fixes in this patchset.

[-- Attachment #2: dwc3_fixes_logs.tar.gz --]
[-- Type: application/x-gzip, Size: 10518 bytes --]

Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 1577 bytes --]

Hi,

On Tue, Jan 06, 2015 at 11:44:23AM +0530, Amit Virdi wrote:
> >>>>I can certainly provide the dwc3 specific kernel bootup logs, full
> >>>>regdump and any loglevel you want me to, if that helps
> >>>
> >>>Yeah, if you can provide those, then that'll help me verifying. Full
> >>>logs from boot to failure point with VERBOSE_DEBUG enabled (considering
> >>>you're not running on anything recent).
> >>>
> >>
> >>Okay. I'll provide full verbose logs, along with the register dump,
> >>when I'm back to the office next week, for the working and non-working
> >>case, but how - as attachment or as inline?
> >
> >Either way will do but I have a feeling mailing list attachment size
> >will bite you, so maybe it's best to make a tarball of both logs and
> >send that as attachment. Compressed text will be very small.
> >
> 
> Attached are the dwc3 verbose logs and register dump without and with the
> fixes in this patchset.

Sorry for the long delay, it has been a bit hectic.

I can see from your logs that we end up with a Transfer Not Ready
(Transfer Active) event and endpoint has BUSY flag set. I also see that
you're queueing 31 requests and all of them will use 2 TRBs, so we
clearly go over our TRB table.

This fix is, indeed, necessary but we need to improve commit log a bit
so it's extremely clear what the error is. Later, we can improve how we
handle requests in this driver, but that is outside of the scope of your
patchset.

Please improve commit log and resend your series so it can be applied.

cheers

-- 
balbi

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Amit Virdi]

On 1/13/2015 12:04 AM, Felipe Balbi wrote:
> Hi,
>
> On Tue, Jan 06, 2015 at 11:44:23AM +0530, Amit Virdi wrote:
>>>>>> I can certainly provide the dwc3 specific kernel bootup logs, full
>>>>>> regdump and any loglevel you want me to, if that helps
>>>>>
>>>>> Yeah, if you can provide those, then that'll help me verifying. Full
>>>>> logs from boot to failure point with VERBOSE_DEBUG enabled (considering
>>>>> you're not running on anything recent).
>>>>>
>>>>
>>>> Okay. I'll provide full verbose logs, along with the register dump,
>>>> when I'm back to the office next week, for the working and non-working
>>>> case, but how - as attachment or as inline?
>>>
>>> Either way will do but I have a feeling mailing list attachment size
>>> will bite you, so maybe it's best to make a tarball of both logs and
>>> send that as attachment. Compressed text will be very small.
>>>
>>
>> Attached are the dwc3 verbose logs and register dump without and with the
>> fixes in this patchset.
>
> Sorry for the long delay, it has been a bit hectic.
>

It's okay!

> I can see from your logs that we end up with a Transfer Not Ready
> (Transfer Active) event and endpoint has BUSY flag set. I also see that
> you're queueing 31 requests and all of them will use 2 TRBs, so we
> clearly go over our TRB table.
>
> This fix is, indeed, necessary but we need to improve commit log a bit
> so it's extremely clear what the error is. Later, we can improve how we
> handle requests in this driver, but that is outside of the scope of your
> patchset.
>
> Please improve commit log and resend your series so it can be applied.
>

Alright! I'll improve the commit messages and, also, cc stable list 
while resending the patches. As I see, you have already picked patches 
[3/4] and [4/4]. So, I'll resend only [1/4] and [2/4]

> cheers
>

Thank you for your patience and kind understanding.
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Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Felipe Balbi]

[-- Attachment #1: Type: text/plain, Size: 2262 bytes --]

Hi,

On Tue, Jan 13, 2015 at 10:18:20AM +0530, Amit Virdi wrote:
> On 1/13/2015 12:04 AM, Felipe Balbi wrote:
> >Hi,
> >
> >On Tue, Jan 06, 2015 at 11:44:23AM +0530, Amit Virdi wrote:
> >>>>>>I can certainly provide the dwc3 specific kernel bootup logs, full
> >>>>>>regdump and any loglevel you want me to, if that helps
> >>>>>
> >>>>>Yeah, if you can provide those, then that'll help me verifying. Full
> >>>>>logs from boot to failure point with VERBOSE_DEBUG enabled (considering
> >>>>>you're not running on anything recent).
> >>>>>
> >>>>
> >>>>Okay. I'll provide full verbose logs, along with the register dump,
> >>>>when I'm back to the office next week, for the working and non-working
> >>>>case, but how - as attachment or as inline?
> >>>
> >>>Either way will do but I have a feeling mailing list attachment size
> >>>will bite you, so maybe it's best to make a tarball of both logs and
> >>>send that as attachment. Compressed text will be very small.
> >>>
> >>
> >>Attached are the dwc3 verbose logs and register dump without and with the
> >>fixes in this patchset.
> >
> >Sorry for the long delay, it has been a bit hectic.
> >
> 
> It's okay!
> 
> >I can see from your logs that we end up with a Transfer Not Ready
> >(Transfer Active) event and endpoint has BUSY flag set. I also see that
> >you're queueing 31 requests and all of them will use 2 TRBs, so we
> >clearly go over our TRB table.
> >
> >This fix is, indeed, necessary but we need to improve commit log a bit
> >so it's extremely clear what the error is. Later, we can improve how we
> >handle requests in this driver, but that is outside of the scope of your
> >patchset.
> >
> >Please improve commit log and resend your series so it can be applied.
> >
> 
> Alright! I'll improve the commit messages and, also, cc stable list while
> resending the patches. As I see, you have already picked patches [3/4] and
> [4/4]. So, I'll resend only [1/4] and [2/4]
> 
> >cheers
> >
> 
> Thank you for your patience and kind understanding.

Alright, I just applied your patches to testing/fixes. I'll start
testing today and should be able to send a pull request to Greg by the
end of the week, hopefully.

cheers

-- 
balbi

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Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Amit Virdi]

> Alright, I just applied your patches to testing/fixes. I'll start
> testing today and should be able to send a pull request to Greg by the
> end of the week, hopefully.
>

Thanks! Just a small clarification - git failed to send patches to 
stable kernel list again (unfortunately I used the older configuration; 
so older git version - my bad).

Does these patches land up in the stable trees through maintainers or I 
should explicitly cc stable@vger.kernel.org now?

Re: [PATCH 2/4] usb: dwc3: gadget: Stop TRB preparation after limit is reached

[Greg KH]

On Wed, Jan 14, 2015 at 02:39:55PM +0530, Amit Virdi wrote:
> >Alright, I just applied your patches to testing/fixes. I'll start
> >testing today and should be able to send a pull request to Greg by the
> >end of the week, hopefully.
> >
> 
> Thanks! Just a small clarification - git failed to send patches to stable
> kernel list again (unfortunately I used the older configuration; so older
> git version - my bad).
> 
> Does these patches land up in the stable trees through maintainers or I
> should explicitly cc stable@vger.kernel.org now?

Please read Documentation/stable_kernel_rules.txt for how to get patches
accepted into the stable trees.

thanks,

greg k-h

[PATCH 4/4] usb: dwc3: Remove current_trb as it is unused

[Amit Virdi]

This field was introduced but never used. So, remove it.

Signed-off-by: Amit Virdi <amit.virdi-qxv4g6HH51o@public.gmane.org>
---
 drivers/usb/dwc3/core.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 4bb9aa696ede..0842aa80976f 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -431,7 +431,6 @@ struct dwc3_event_buffer {
  * @dwc: pointer to DWC controller
  * @saved_state: ep state saved during hibernation
  * @flags: endpoint flags (wedged, stalled, ...)
- * @current_trb: index of current used trb
  * @number: endpoint number (1 - 15)
  * @type: set to bmAttributes & USB_ENDPOINT_XFERTYPE_MASK
  * @resource_index: Resource transfer index
@@ -464,8 +463,6 @@ struct dwc3_ep {
 	/* This last one is specific to EP0 */
 #define DWC3_EP0_DIR_IN		(1 << 31)
 
-	unsigned		current_trb;