Re: [PATCH] arm64: dts: qcom: sc8280xp: fix PCIe DMA coherency
flat view
From: Johan Hovold <johan@kernel.org>
Date: 2022-11-25 15:49:52
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On Fri, Nov 25, 2022 at 08:23:36PM +0530, Manivannan Sadhasivam wrote:
On Fri, Nov 25, 2022 at 03:43:59PM +0100, Johan Hovold wrote:quoted
On Fri, Nov 25, 2022 at 07:56:25PM +0530, Manivannan Sadhasivam wrote:quoted
On Thu, Nov 24, 2022 at 03:25:01PM +0100, Johan Hovold wrote:
quoted
I never claimed it would fix the problem, I explicitly wrote that it made it less likely to occur (to the point where my reproducer no longer triggers).quoted
Increasing the buffer sizes to two pages to force CMA allocation also appears to make the problem go away.The "go away" part sounded like a claim to me and hence I added the statement. But no worries :)
Hopefully it's clear enough if you also read the preceding sentence (with emphasis added): presumably as these queues are small enough to not be allocated using CMA which in turn make them *more likely to be cached* (e.g. due to accesses to nearby pages through the cacheable linear map). Johan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel