| Message ID | 1467216519-7200-3-git-send-email-jonathanh@nvidia.com |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Wed, Jun 29, 2016 at 05:08:39PM +0100, Jon Hunter wrote: > Commit 71f7e6cc5500 ('dmaengine: tegra20-apb-dma: Only calculate residue > if txstate exists') changed the tegra_dma_tx_status() function to only > calculate the residue if there is a valid 'txstate' pointer for storing > the residue. Although this makes sense, this changed the behaviour of > the function tegra_dma_tx_status() such that if the pointer 'txstate' is > not valid, then we will return whatever state is returned by > dma_cookie_status() and no longer return the state by looking up the DMA > descriptor and returning it's state. > > Please note that dma_cookie_status() will either return DMA_COMPLETE or > DMA_IN_PROGRESS. However, if dma_cookie_status() returns DMA_IN_PROGRESS > the actual status could be DMA_ERROR which will only be seen from > checking the descriptor status. Therefore, even if 'txstate' is not > valid, still check to see if there is a valid descriptor for the cookie > in question and if so return the descriptor state. Finally, ensure the > residue is still not calculated if the 'txstate' is not valid. > > Signed-off-by: Jon Hunter <jonathanh@nvidia.com> > --- > drivers/dma/tegra20-apb-dma.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) Acked-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index 6da9e1032236..6ab9eb98588a 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -811,7 +811,7 @@ 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 || !txstate) + if (ret == DMA_COMPLETE) return ret; spin_lock_irqsave(&tdc->lock, flags); @@ -837,7 +837,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc, dma_desc = NULL; found: - if (dma_desc) { + if (dma_desc && txstate) { residual = dma_desc->bytes_requested - (dma_desc->bytes_transferred % dma_desc->bytes_requested);
Commit 71f7e6cc5500 ('dmaengine: tegra20-apb-dma: Only calculate residue if txstate exists') changed the tegra_dma_tx_status() function to only calculate the residue if there is a valid 'txstate' pointer for storing the residue. Although this makes sense, this changed the behaviour of the function tegra_dma_tx_status() such that if the pointer 'txstate' is not valid, then we will return whatever state is returned by dma_cookie_status() and no longer return the state by looking up the DMA descriptor and returning it's state. Please note that dma_cookie_status() will either return DMA_COMPLETE or DMA_IN_PROGRESS. However, if dma_cookie_status() returns DMA_IN_PROGRESS the actual status could be DMA_ERROR which will only be seen from checking the descriptor status. Therefore, even if 'txstate' is not valid, still check to see if there is a valid descriptor for the cookie in question and if so return the descriptor state. Finally, ensure the residue is still not calculated if the 'txstate' is not valid. Signed-off-by: Jon Hunter <jonathanh@nvidia.com> --- drivers/dma/tegra20-apb-dma.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)