stmmac/RTL8211F/Meson GXBB: TX throughput problems

Martin Blumenstingl martin.blumenstingl at
Sat Oct 1 13:40:59 PDT 2016

On Sat, Oct 1, 2016 at 10:15 PM, Martin Blumenstingl
<martin.blumenstingl at> wrote:
> On Wed, Sep 14, 2016 at 5:30 PM, Giuseppe CAVALLARO
> <peppe.cavallaro at> wrote:
>> Also you could check the AXI tuning and PBL value. To be honest
>> (thinking about your problem) I can actually suspect some related
>> problem on bus setup. So I suggest you to play with these value
>> (better if you ask for having values from HW validation on your side).
>> Otherwise the stmmac uses a default that cannot be good for your
>> platform. For example, sometime I have seen that PBL is better if
>> reduced to 8 instead of 32 and w/o 4xPBL...
> unfortunately the original kernel/firmware shipped with my device
> seems to be also affected by that TX bug, so comparing with the
> "stock" values does not work for me.
I tried the following changes:
- snps,pbl = <4>; in .dts
- snps,pbl = <2>; in .dts
- snps,pbl = <8>; in .dts and disabled DMA_BUS_MODE_MAXPBL (= 4xPBL) in stmmac

None of these seem to have any impact on the TX problem
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