[Letux-kernel] Pyra display driver once again broken in v5.2-rc1

H. Nikolaus Schaller hns at goldelico.com
Wed May 29 06:39:22 CEST 2019

> Am 28.05.2019 um 23:40 schrieb Andreas Kemnade <andreas at kemnade.info>:
> On Mon, 27 May 2019 21:25:41 +0200
> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
>>> Am 27.05.2019 um 14:46 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
>>> Hi,
>>> unfortunately every year or so some upstream change breaks
>>> our (still out-of tree) DSI panel driver for the Pyra(Phone).
>>> This time it happened with v5.2-rc1.
>>> v5.2-rc1 also broke the GTA04 display and the L3704/L7004 displays,
>>> but those are DPI panels and the reasons were two separate
>>> issues which have nothing to do with the Pyra DSI panel.
>>> There have been some API changes for DSI panel drivers and
>>> I have done a
>>> 	git diff v5.2-rc1 v5.1 drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c
>>> to identify them and tried to apply similar patches to our
>>> panel. But still the driver is successfully probed, but shows
>>> not activity. No calls to enable() or connect(). Backlight stays
>>> black. And as a result there is also no /dev/fb0, text console
>>> or X11.
>>> Unfortunately, it has not improved after upgrading to v5.2-rc2.
>>> So once again it appears that I have to git bisect upstream
>>> patches to find out what is going on...  
>> After spending more hours... it does not seem to be in our patches
>> and the panel driver is likely almost correct now.
>> I believe this because I also found not working:
>> * dwc3 (usb3/otg port)
>> * bq24297 battery charger driver (my Pyra fortunately runs well enough with U-Boot initialization)
>> * tca6424 (gpio expander - we use the pcal9524 variant)
>> The tca6424 driver seems to be broken (not loaded).
> [    6.581432] ts3a227e 4-003b: Cannot request irq 0 (-22)
> [    6.597252] ts3a227e: probe of 4-003b failed with error -22
> so somehow it insists of having an irq and we are not providing one in
> the dtb, at least not in pyra-mainboard-v5.1.dtsi

The reference is set in pyra-mainboard-v5.2.dtsi

		interrupt-parent = <&gpio99>;
		interrupts = <14 IRQ_TYPE_EDGE_RISING>;

But: this is another symptom of the tca6424 (gpio99) not being available.
It is not only a gpio expander but also an interrupt expander.

So we should focus on finding out why the tca6424 / pcal6524 does
not probe.

BR and thanks,

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