This is a note to let you know that I've just added the patch titled
serial: 8250_lpss: Use 16B DMA burst with Elkhart Lake
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
serial-8250_lpss-use-16b-dma-burst-with-elkhart-lake.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7090abd6ad0610a144523ce4ffcb8560909bf2a8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Date: Tue, 8 Nov 2022 14:19:51 +0200
Subject: serial: 8250_lpss: Use 16B DMA burst with Elkhart Lake
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From: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
commit 7090abd6ad0610a144523ce4ffcb8560909bf2a8 upstream.
Configure DMA to use 16B burst size with Elkhart Lake. This makes the
bus use more efficient and works around an issue which occurs with the
previously used 1B.
The fix was initially developed by Srikanth Thokala and Aman Kumar.
This together with the previous config change is the cleaned up version
of the original fix.
Fixes: 0a9410b981e9 ("serial: 8250_lpss: Enable DMA on Intel Elkhart Lake")
Cc: <stable@xxxxxxxxxxxxxxx> # serial: 8250_lpss: Configure DMA also w/o DMA filter
Reported-by: Wentong Wu <wentong.wu@xxxxxxxxx>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221108121952.5497-4-ilpo.jarvinen@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_lpss.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/tty/serial/8250/8250_lpss.c
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -177,6 +177,9 @@ static int ehl_serial_setup(struct lpss8
* matching with the registered General Purpose DMA controllers.
*/
up->dma = dma;
+
+ lpss->dma_maxburst = 16;
+
return 0;
}
Patches currently in stable-queue which might be from ilpo.jarvinen@xxxxxxxxxxxxxxx are
queue-5.15/serial-8250_lpss-use-16b-dma-burst-with-elkhart-lake.patch
queue-5.15/serial-8250-flush-dma-rx-on-rlsi.patch
queue-5.15/serial-8250_lpss-configure-dma-also-w-o-dma-filter.patch
queue-5.15/serial-8250-fall-back-to-non-dma-rx-if-iir_rdi-occurs.patch
queue-5.15/serial-8250_omap-remove-wait-loop-from-errata-i202-w.patch
