On 10/22/19 11:24 AM, Adrian Chadd wrote:
On Tue, 22 Oct 2019 at 10:17, Peter Oh <peter.oh@xxxxxxxx> wrote:
On 10/22/19 1:57 AM, Zhi Chen wrote:
This reverts commit 76d164f582150fd0259ec0fcbc485470bcd8033e.
PCIe hung issue was observed on multiple platforms. The issue was reproduced
when DUT was configured as AP and associated with 50+ STAs.
With PCIe protocol analyzer, we can see DMA Read crossing 4KB boundary when
issue happened. It broke PCIe spec and caused PCIe stuck.
Can you elaborate how 64 bytes DMA size breaks PCIe spec?
How can you say value 0 (I believe it's 64 bytes) DMA burst size causes
the symptom and 1 fixes it?
+1 to this question.
Also, shouldn't the DMA engine be doing what the firmware says? Is the
firmware/copy engine actually somehow bursting / prefetching across a
4K page boundary?
Surely this is something that can be fixed in software/firmware by
correctly configuring up buffer size/offsets?
-adrian
