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Subject: [BUG] SPI broken for SPI based panel drivers
From:   "H. Nikolaus Schaller" <hns@goldelico.com>
Date:   Mon, 30 Nov 2020 20:03:23 +0100
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Mark Brown <broonie@kernel.org>,
        kernel list <linux-kernel@vger.kernel.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Discussions about the Letux Kernel 
        <letux-kernel@openphoenux.org>
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Message-Id: <2D7916FA-678F-4236-B478-C953CADF2FFA@goldelico.com>
To:     Sven Van Asbroeck <thesven73@gmail.com>
Precedence: bulk

Hi,
starting from v5.10-rc5 the SPI based panel of the GTA04 device is =
broken. It uses
compatible =3D "spi-gpio"; [1] i.e. gpio descriptors very indirectly.

Bisect shows that it is commit

766c6b63aa04 ("spi: fix client driver breakages when using GPIO =
descriptors")

The commit description tells about a problematic pattern and indeed the =
driver is
using it - like ca. 15 other spi based panel drivers in =
drivers/gpu/drm/panel/

I understood that it wants to fix the spi system to handle that =
correctly again.
But reverting your patch brings back the display. So it appears as if it =
does not
fix a breakage, rather breaks a previously working setup.

What should we do?

BR and thanks,
Nikolaus

[1]: =
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/ar=
ch/arm/boot/dts/omap3-gta04.dtsi?h=3Dv5.10-rc6#n107