Re: [PATCH 7/8] dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists.
On Tue, Jun 21, 2016 at 06:19:50PM +0100, Jon Hunter wrote: > > On 21/06/16 17:01, Vinod Koul wrote: > > On Wed, Jun 08, 2016 at 09:51:57AM +0100, Jon Hunter wrote: > >> Hi Peter, > >> > >> On 07/06/16 18:38, Peter Griffin wrote: > >>> There is no point calculating the residue if there is > >>> no txstate to store the value. > >>> > >>> Signed-off-by: Peter Griffin > >>> --- > >>> drivers/dma/tegra20-apb-dma.c | 2 +- > >>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>> > >>> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c > >>> index 01e316f..7f4af8c 100644 > >>> --- a/drivers/dma/tegra20-apb-dma.c > >>> +++ b/drivers/dma/tegra20-apb-dma.c > >>> @@ -814,7 +814,7 @@ static enum dma_status tegra_dma_tx_status(struct > >>> dma_chan *dc, > >>> unsigned int residual; > >>> > >>> ret = dma_cookie_status(dc, cookie, txstate); > >>> - if (ret == DMA_COMPLETE) > >>> + if (ret == DMA_COMPLETE || !txstate) > >>> return ret; > >> > >> Thanks for reporting this. I agree that we should not do this, however, > >> looking at the code for Tegra, I am wondering if this could change the > >> actual state that is returned. Looking at dma_cookie_status() it will > >> call dma_async_is_complete() which will return either DMA_COMPLETE or > >> DMA_IN_PROGRESS. It could be possible that the actual state for the > >> DMA transfer in the tegra driver is DMA_ERROR, so I am wondering if we > >> should do something like the following ... > > > > This one is stopping code execution when residue is not valid. Do notice > > that it check for DMA_COMPLETE OR txstate. In other cases, wit will return > > 'that' state when txstate is NULL. > > Sorry what do you mean by "this one"? the patch > > My point is that if the status is not DMA_COMPLETE, then it is possible > that it could be DMA_ERROR (for tegra that is). right it can be any state... and we check for only DMA_COMPLETE as residue has no meaning. > However, > dma_cookie_status will only return DMA_IN_PROGRESS or DMA_COMPLETE and > so if 'txstate' is NULL we will not see the DMA_ERROR status anymore and > just think it is in progress when it is actually an error. Yes that is an existing issue, if you are reporting DMA_ERROR then you should add a check for DMA_ERROR as well and not do residue calculation for that case. > > I do agree that the driver is broken as we are not checking for > !txstate, but this also changes the behaviour a bit. It changes for better and not worse. Btw pls feel free to send a patch handling DMA_ERROR :) -- ~Vinod
Re: [PATCH 7/8] dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists.
On 21/06/16 17:01, Vinod Koul wrote: > On Wed, Jun 08, 2016 at 09:51:57AM +0100, Jon Hunter wrote: >> Hi Peter, >> >> On 07/06/16 18:38, Peter Griffin wrote: >>> There is no point calculating the residue if there is >>> no txstate to store the value. >>> >>> Signed-off-by: Peter Griffin >>> --- >>> drivers/dma/tegra20-apb-dma.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c >>> index 01e316f..7f4af8c 100644 >>> --- a/drivers/dma/tegra20-apb-dma.c >>> +++ b/drivers/dma/tegra20-apb-dma.c >>> @@ -814,7 +814,7 @@ static enum dma_status tegra_dma_tx_status(struct >>> dma_chan *dc, >>> unsigned int residual; >>> >>> ret = dma_cookie_status(dc, cookie, txstate); >>> - if (ret == DMA_COMPLETE) >>> + if (ret == DMA_COMPLETE || !txstate) >>> return ret; >> >> Thanks for reporting this. I agree that we should not do this, however, >> looking at the code for Tegra, I am wondering if this could change the >> actual state that is returned. Looking at dma_cookie_status() it will >> call dma_async_is_complete() which will return either DMA_COMPLETE or >> DMA_IN_PROGRESS. It could be possible that the actual state for the >> DMA transfer in the tegra driver is DMA_ERROR, so I am wondering if we >> should do something like the following ... > > This one is stopping code execution when residue is not valid. Do notice > that it check for DMA_COMPLETE OR txstate. In other cases, wit will return > 'that' state when txstate is NULL. Sorry what do you mean by "this one"? My point is that if the status is not DMA_COMPLETE, then it is possible that it could be DMA_ERROR (for tegra that is). However, dma_cookie_status will only return DMA_IN_PROGRESS or DMA_COMPLETE and so if 'txstate' is NULL we will not see the DMA_ERROR status anymore and just think it is in progress when it is actually an error. I do agree that the driver is broken as we are not checking for !txstate, but this also changes the behaviour a bit. Cheers Jon -- nvpublic
Re: [PATCH 7/8] dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists.
On Wed, Jun 08, 2016 at 09:51:57AM +0100, Jon Hunter wrote:
> Hi Peter,
>
> On 07/06/16 18:38, Peter Griffin wrote:
> > There is no point calculating the residue if there is
> > no txstate to store the value.
> >
> > Signed-off-by: Peter Griffin
> > ---
> > drivers/dma/tegra20-apb-dma.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> > index 01e316f..7f4af8c 100644
> > --- a/drivers/dma/tegra20-apb-dma.c
> > +++ b/drivers/dma/tegra20-apb-dma.c
> > @@ -814,7 +814,7 @@ static enum dma_status tegra_dma_tx_status(struct
> > dma_chan *dc,
> > unsigned int residual;
> >
> > ret = dma_cookie_status(dc, cookie, txstate);
> > - if (ret == DMA_COMPLETE)
> > + if (ret == DMA_COMPLETE || !txstate)
> > return ret;
>
> Thanks for reporting this. I agree that we should not do this, however,
> looking at the code for Tegra, I am wondering if this could change the
> actual state that is returned. Looking at dma_cookie_status() it will
> call dma_async_is_complete() which will return either DMA_COMPLETE or
> DMA_IN_PROGRESS. It could be possible that the actual state for the
> DMA transfer in the tegra driver is DMA_ERROR, so I am wondering if we
> should do something like the following ...
This one is stopping code execution when residue is not valid. Do notice
that it check for DMA_COMPLETE OR txstate. In other cases, wit will return
'that' state when txstate is NULL.
I am going to apply this.
>
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index 01e316f73559..45edab7418d0 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -822,13 +822,8 @@ static enum dma_status tegra_dma_tx_status(struct
> dma_chan *dc,
> /* Check on wait_ack desc status */
> list_for_each_entry(dma_desc, &tdc->free_dma_desc, node) {
> if (dma_desc->txd.cookie == cookie) {
> - residual = dma_desc->bytes_requested -
> - (dma_desc->bytes_transferred %
> - dma_desc->bytes_requested);
> - dma_set_residue(txstate, residual);
> ret = dma_desc->dma_status;
> - spin_unlock_irqrestore(&tdc->lock, flags);
> - return ret;
> + goto found;
> }
> }
>
> @@ -836,17 +831,23 @@ static enum dma_status tegra_dma_tx_status(struct
> dma_chan *dc,
> list_for_each_entry(sg_req, &tdc->pending_sg_req, node) {
> dma_desc = sg_req->dma_desc;
> if (dma_desc->txd.cookie == cookie) {
> - residual = dma_desc->bytes_requested -
> - (dma_desc->bytes_transferred %
> - dma_desc->bytes_requested);
> - dma_set_residue(txstate, residual);
> ret = dma_desc->dma_status;
> - spin_unlock_irqrestore(&tdc->lock, flags);
> - return ret;
> + goto found;
> }
> }
>
> - dev_dbg(tdc2dev(tdc), "cookie %d does not found\n", cookie);
> + dev_warn(tdc2dev(tdc), "cookie %d not found\n", cookie);
> + spin_unlock_irqrestore(&tdc->lock, flags);
> + return ret;
> +
> +found:
> + if (txstate) {
> + residual = dma_desc->bytes_requested -
> + (dma_desc->bytes_transferred %
> + dma_desc->bytes_requested);
> + dma_set_residue(txstate, residual);
> + }
> +
I feel this optimizes stuff, which seems okay. Feel free to send as proper
patch.
> spin_unlock_irqrestore(&tdc->lock, flags);
> return ret;
> }
>
> Cheers
> Jon
>
> --
> nvpublic
--
~Vinod
Re: [PATCH 7/8] dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists.
Hi Peter,
On 07/06/16 18:38, Peter Griffin wrote:
> There is no point calculating the residue if there is
> no txstate to store the value.
>
> Signed-off-by: Peter Griffin
> ---
> drivers/dma/tegra20-apb-dma.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index 01e316f..7f4af8c 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -814,7 +814,7 @@ static enum dma_status tegra_dma_tx_status(struct
> dma_chan *dc,
> unsigned int residual;
>
> ret = dma_cookie_status(dc, cookie, txstate);
> - if (ret == DMA_COMPLETE)
> + if (ret == DMA_COMPLETE || !txstate)
> return ret;
Thanks for reporting this. I agree that we should not do this, however,
looking at the code for Tegra, I am wondering if this could change the
actual state that is returned. Looking at dma_cookie_status() it will
call dma_async_is_complete() which will return either DMA_COMPLETE or
DMA_IN_PROGRESS. It could be possible that the actual state for the
DMA transfer in the tegra driver is DMA_ERROR, so I am wondering if we
should do something like the following ...
diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 01e316f73559..45edab7418d0 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -822,13 +822,8 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan
*dc,
/* Check on wait_ack desc status */
list_for_each_entry(dma_desc, &tdc->free_dma_desc, node) {
if (dma_desc->txd.cookie == cookie) {
- residual = dma_desc->bytes_requested -
- (dma_desc->bytes_transferred %
- dma_desc->bytes_requested);
- dma_set_residue(txstate, residual);
ret = dma_desc->dma_status;
- spin_unlock_irqrestore(&tdc->lock, flags);
- return ret;
+ goto found;
}
}
@@ -836,17 +831,23 @@ static enum dma_status tegra_dma_tx_status(struct
dma_chan *dc,
list_for_each_entry(sg_req, &tdc->pending_sg_req, node) {
dma_desc = sg_req->dma_desc;
if (dma_desc->txd.cookie == cookie) {
- residual = dma_desc->bytes_requested -
- (dma_desc->bytes_transferred %
- dma_desc->bytes_requested);
- dma_set_residue(txstate, residual);
ret = dma_desc->dma_status;
- spin_unlock_irqrestore(&tdc->lock, flags);
- return ret;
+ goto found;
}
}
- dev_dbg(tdc2dev(tdc), "cookie %d does not found\n", cookie);
+ dev_warn(tdc2dev(tdc), "cookie %d not found\n", cookie);
+ spin_unlock_irqrestore(&tdc->lock, flags);
+ return ret;
+
+found:
+ if (txstate) {
+ residual = dma_desc->bytes_requested -
+ (dma_desc->bytes_transferred %
+ dma_desc->bytes_requested);
+ dma_set_residue(txstate, residual);
+ }
+
spin_unlock_irqrestore(&tdc->lock, flags);
return ret;
}
Cheers
Jon
--
nvpublic
[PATCH 7/8] dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists.
There is no point calculating the residue if there is no txstate to store the value. Signed-off-by: Peter Griffin --- drivers/dma/tegra20-apb-dma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index 01e316f..7f4af8c 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -814,7 +814,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc, unsigned int residual; ret = dma_cookie_status(dc, cookie, txstate); - if (ret == DMA_COMPLETE) + if (ret == DMA_COMPLETE || !txstate) return ret; spin_lock_irqsave(&tdc->lock, flags); -- 1.9.1
