From: Peter Hess <email@example.com>
To: Guenter Roeck <firstname.lastname@example.org>, email@example.com
Cc: stable <firstname.lastname@example.org>,
Greg Kroah-Hartman <email@example.com>,
Frank Wunderlich <firstname.lastname@example.org>,
Mark Brown <email@example.com>
Subject: Re: regression [fixed]: SPI interface on systems with Mediatek CPU broken
Date: Mon, 9 Aug 2021 00:13:58 +0200 [thread overview]
Message-ID: <firstname.lastname@example.org> (raw)
I would like to apologize for the inconvenience caused by my submitted
patch. I should have looked deeper into the driver, then this would not
have happened with the RX path. Unfortunately, the faulty patch still
worked on my system and so I didn't realize the error. In the future I
will pay more attention to the whole context in the hope that this will
not happen again.
Am 07.08.2021 um 00:33 schrieb Guenter Roeck:
> [ submitted for reference. The problem has now been fixed in the
> upstream kernel ]
> Affected upstream kernel releases: v5.14-rc3, v5.14-rc4
> Various stable releases with the problematic commit are also affected.
> The SPI interface on systems with various Mediatek CPUs is not
> The problem affects all Chromebooks with Mediatek CPU since those
> use the SPI interface to connect to the Embedded Controller.
> Bisect suggests that commit 3a70dd2d050 ("spi: mediatek: fix fifo rx
> introduced the problem. The problem was fixed with upstream commit
> ("spi: mediatek: Fix fifo transfer").
> Detailed problem description from commit 0d5c3954b35e:
> Commit 3a70dd2d0503 ("spi: mediatek: fix fifo rx mode") claims that
> fifo RX mode was never handled, and adds the presumably missing code
> to the FIFO transfer function. However, the claim that receive data
> was not handled is incorrect. It was handled as part of interrupt
> handling after the transfer was complete. The code added with the
> mentioned commit reads data from the receive FIFO before the transfer
> is started, which is wrong. This results in an actual transfer error
> on a Hayato Chromebook.
> Remove the code trying to handle receive data before the transfer is
> started to fix the problem.
prev parent reply other threads:[~2021-08-08 22:27 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-06 22:33 regression [fixed]: SPI interface on systems with Mediatek CPU broken Guenter Roeck
2021-08-08 22:13 ` Peter Hess [this message]
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