| Message ID | 1309356549.3995.13.camel@quad (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
* Scott Ellis <scott@jumpnowtek.com> [110629 20:58]: > Break from dma channel search when a free one is found. Care to describe how the current code is not finding a free channel currently? Tony > Signed-off-by: Scott Ellis <scott@jumpnowtek.com> > --- > arch/arm/plat-omap/dma.c | 5 ++--- > 1 files changed, 2 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c > index c22217c..3d36fcf 100644 > --- a/arch/arm/plat-omap/dma.c > +++ b/arch/arm/plat-omap/dma.c > @@ -678,10 +678,9 @@ int omap_request_dma(int dev_id, const char *dev_name, > > spin_lock_irqsave(&dma_chan_lock, flags); > for (ch = 0; ch < dma_chan_count; ch++) { > - if (free_ch == -1 && dma_chan[ch].dev_id == -1) { > + if (dma_chan[ch].dev_id == -1) { > free_ch = ch; > - if (dev_id == 0) > - break; > + break; > } > } > if (free_ch == -1) { >
A free channel gets found correctly, that's not the problem. The patch is to eliminate the extra passes through the loop after free_ch is assigned. I dropped some printk's into omap_request_dma() [ 158.375885] inside omap_request_dma() [ 158.379577] dev_id = 61 ch = 0 free_ch = -1 [ 158.383789] dev_id = 61 ch = 1 free_ch = -1 [ 158.387969] dev_id = 61 ch = 2 free_ch = -1 [ 158.392181] dev_id = 61 ch = 3 free_ch = -1 [ 158.396392] dev_id = 61 ch = 4 free_ch = -1 [ 158.400573] set free_ch = 4 (could break now) [ 158.403381] dev_id = 61 ch = 5 free_ch = 4 [ 158.407501] dev_id = 61 ch = 6 free_ch = 4 [ 158.411621] dev_id = 61 ch = 7 free_ch = 4 [ 158.415740] dev_id = 61 ch = 8 free_ch = 4 [ 158.419830] dev_id = 61 ch = 9 free_ch = 4 [ 158.423950] dev_id = 61 ch = 10 free_ch = 4 [ 158.428161] dev_id = 61 ch = 11 free_ch = 4 [ 158.432373] dev_id = 61 ch = 12 free_ch = 4 [ 158.436553] dev_id = 61 ch = 13 free_ch = 4 [ 158.440765] dev_id = 61 ch = 14 free_ch = 4 [ 158.444976] dev_id = 61 ch = 15 free_ch = 4 [ 158.449157] dev_id = 61 ch = 16 free_ch = 4 [ 158.453369] dev_id = 61 ch = 17 free_ch = 4 [ 158.457580] dev_id = 61 ch = 18 free_ch = 4 [ 158.461761] dev_id = 61 ch = 19 free_ch = 4 [ 158.465972] dev_id = 61 ch = 20 free_ch = 4 [ 158.470184] dev_id = 61 ch = 21 free_ch = 4 [ 158.474395] dev_id = 61 ch = 22 free_ch = 4 [ 158.478576] dev_id = 61 ch = 23 free_ch = 4 [ 158.482788] dev_id = 61 ch = 24 free_ch = 4 [ 158.486999] dev_id = 61 ch = 25 free_ch = 4 [ 158.491180] dev_id = 61 ch = 26 free_ch = 4 [ 158.495391] dev_id = 61 ch = 27 free_ch = 4 [ 158.499603] dev_id = 61 ch = 28 free_ch = 4 [ 158.503784] dev_id = 61 ch = 29 free_ch = 4 [ 158.507995] dev_id = 61 ch = 30 free_ch = 4 [ 158.512207] dev_id = 61 ch = 31 free_ch = 4 ... [ 4.097991] inside omap_request_dma() [ 4.101684] dev_id = 62 ch = 0 free_ch = -1 [ 4.105895] dev_id = 62 ch = 1 free_ch = -1 [ 4.110076] dev_id = 62 ch = 2 free_ch = -1 [ 4.114288] dev_id = 62 ch = 3 free_ch = -1 [ 4.118499] dev_id = 62 ch = 4 free_ch = -1 [ 4.122680] set free_ch = 4 (could break now) [ 4.125488] dev_id = 62 ch = 5 free_ch = 4 [ 4.129608] dev_id = 62 ch = 6 free_ch = 4 [ 4.133728] dev_id = 62 ch = 7 free_ch = 4 [ 4.137847] dev_id = 62 ch = 8 free_ch = 4 [ 4.141937] dev_id = 62 ch = 9 free_ch = 4 [ 4.146057] dev_id = 62 ch = 10 free_ch = 4 [ 4.150268] dev_id = 62 ch = 11 free_ch = 4 [ 4.154479] dev_id = 62 ch = 12 free_ch = 4 [ 4.158660] dev_id = 62 ch = 13 free_ch = 4 [ 4.162872] dev_id = 62 ch = 14 free_ch = 4 [ 4.167083] dev_id = 62 ch = 15 free_ch = 4 [ 4.171264] dev_id = 62 ch = 16 free_ch = 4 [ 4.175476] dev_id = 62 ch = 17 free_ch = 4 [ 4.179687] dev_id = 62 ch = 18 free_ch = 4 [ 4.183868] dev_id = 62 ch = 19 free_ch = 4 [ 4.188079] dev_id = 62 ch = 20 free_ch = 4 [ 4.192291] dev_id = 62 ch = 21 free_ch = 4 [ 4.196502] dev_id = 62 ch = 22 free_ch = 4 [ 4.200683] dev_id = 62 ch = 23 free_ch = 4 [ 4.204895] dev_id = 62 ch = 24 free_ch = 4 [ 4.209106] dev_id = 62 ch = 25 free_ch = 4 [ 4.213287] dev_id = 62 ch = 26 free_ch = 4 [ 4.217498] dev_id = 62 ch = 27 free_ch = 4 [ 4.221710] dev_id = 62 ch = 28 free_ch = 4 [ 4.225891] dev_id = 62 ch = 29 free_ch = 4 [ 4.230102] dev_id = 62 ch = 30 free_ch = 4 [ 4.234313] dev_id = 62 ch = 31 free_ch = 4 ... I was also wondering, what is special about dev_id == 0? The current code treats that special and does break immediately? Scott On Fri, 2011-07-01 at 00:19 -0700, Tony Lindgren wrote: > * Scott Ellis <scott@jumpnowtek.com> [110629 20:58]: > > Break from dma channel search when a free one is found. > > Care to describe how the current code is not finding a > free channel currently? > > Tony > > > > Signed-off-by: Scott Ellis <scott@jumpnowtek.com> > > --- > > arch/arm/plat-omap/dma.c | 5 ++--- > > 1 files changed, 2 insertions(+), 3 deletions(-) > > > > diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c > > index c22217c..3d36fcf 100644 > > --- a/arch/arm/plat-omap/dma.c > > +++ b/arch/arm/plat-omap/dma.c > > @@ -678,10 +678,9 @@ int omap_request_dma(int dev_id, const char *dev_name, > > > > spin_lock_irqsave(&dma_chan_lock, flags); > > for (ch = 0; ch < dma_chan_count; ch++) { > > - if (free_ch == -1 && dma_chan[ch].dev_id == -1) { > > + if (dma_chan[ch].dev_id == -1) { > > free_ch = ch; > > - if (dev_id == 0) > > - break; > > + break; > > } > > } > > if (free_ch == -1) { > >
diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c index c22217c..3d36fcf 100644 --- a/arch/arm/plat-omap/dma.c +++ b/arch/arm/plat-omap/dma.c @@ -678,10 +678,9 @@ int omap_request_dma(int dev_id, const char *dev_name, spin_lock_irqsave(&dma_chan_lock, flags); for (ch = 0; ch < dma_chan_count; ch++) { - if (free_ch == -1 && dma_chan[ch].dev_id == -1) { + if (dma_chan[ch].dev_id == -1) { free_ch = ch; - if (dev_id == 0) - break; + break; } } if (free_ch == -1) {
Break from dma channel search when a free one is found. Signed-off-by: Scott Ellis <scott@jumpnowtek.com> --- arch/arm/plat-omap/dma.c | 5 ++--- 1 files changed, 2 insertions(+), 3 deletions(-)