From: Tony Lindgren <tony@atomide.com>
To: Andreas Kemnade <andreas@kemnade.info>
Cc: bcousson@baylibre.com, robh+dt@kernel.org,
krzysztof.kozlowski+dt@linaro.org, aford173@gmail.com,
linux-omap@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org,
"H. Nikolaus Schaller" <hns@goldelico.com>
Subject: Re: [PATCH] ARM: dts: gta04: fix excess dma channel usage
Date: Mon, 27 Mar 2023 11:13:27 +0300 [thread overview]
Message-ID: <20230327081327.GE7501@atomide.com> (raw)
In-Reply-To: <20230113211151.2314874-1-andreas@kemnade.info>
* Andreas Kemnade <andreas@kemnade.info> [230113 23:12]:
> From: "H. Nikolaus Schaller" <hns@goldelico.com>
>
> OMAP processors support 32 channels but there is no check or
> inspect this except booting a device and looking at dmesg reports
> of not available channels.
>
> Recently some more subsystems with DMA (aes1+2) were added filling
> the list of dma channels beyond the limit of 32 (even if other
> parameters indicate 96 or 128 channels). This leads to random
> subsystem failures i(e.g. mcbsp for audio) after boot or boot
> messages that DMA can not be initialized.
>
> Another symptom is that
>
> /sys/kernel/debug/dmaengine/summary
>
> has 32 entries and does not show all required channels.
>
> Fix by disabling unused (on the GTA04 hardware) mcspi1...4.
> Each SPI channel allocates 4 DMA channels rapidly filling
> the available ones.
>
> Disabling unused SPI modules on the OMAP3 SoC may also save
> some energy (has not been checked).
Applying this into omap-for-v6.4/dt based on what we discussed
in this thread earlier.
Thanks,
Tony
prev parent reply other threads:[~2023-03-27 8:13 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-13 21:11 [PATCH] ARM: dts: gta04: fix excess dma channel usage Andreas Kemnade
2023-01-16 14:16 ` Adam Ford
2023-01-16 14:51 ` Tony Lindgren
2023-01-16 15:29 ` H. Nikolaus Schaller
2023-01-16 17:00 ` Tony Lindgren
2023-01-16 16:39 ` Andreas Kemnade
2023-01-16 16:56 ` Tony Lindgren
2023-01-16 17:00 ` Adam Ford
2023-01-16 17:08 ` Tony Lindgren
2023-01-19 7:30 ` Tony Lindgren
2023-01-22 9:08 ` Andreas Kemnade
2024-11-07 9:35 ` Andreas Kemnade
2023-03-27 8:13 ` Tony Lindgren [this message]
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