Re: [PATCH 1/1] ACPI: video: Add Toshiba Satellite/Portege Z830 quirk

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 8/27/22 15:49, Hans de Goede wrote:
> hI,
> 
> On 8/27/22 13:23, Arvid Norlander wrote:
>> Hi,
>>
>> On 2022-08-26 13:46, Hans de Goede wrote:
>>> Hi All,
>>>
>>> [...]
>>>
>>> Arvid, I wonder if instead of using disable_backlight_sysfs_if
>>> you can try:
>>>
>>> 0. Remove disable_backlight_sysfs_if from cmdline / quirk
>>> 1. Adding acpi_backlight=native to the kernel commandline
>>> 2. In toshiba_acpi_resume() add a HCI_PANEL_POWER_ON PANEL_ON
>>>
>>> and see if that also fixes things ?
>>>
>> Yes, this works.
> 
> Great, thank you for testing this!
> 
> In hindsight the disable_backlight_sysfs_if flag was a mistake
> and I should have fixed this differently (I wrote the code adding
> that flag).  And now it is sorta getting in the way of cleaning
> up the backlight handling. So IMHO removing disable_backlight_sysfs_if
> is the best thing to do here.
> 
>> I do not have a patch for this (I assume it
>> would involve creating quirk tables, checking for support for
>> HCI_PANEL_POWER_ON, etc). I simply hard coded the call in for
>> the test. I very much doubt I will have time to code this in
>> the near future as well.
> 
> No problem I will prepare a patch series for you to test. Note
> this will be on top of my other backlight cleanups, so I
> will just send you an email pointing to a git branch to test,
> I hope this will be ok?

Arvid, here is a git branch with my backlight-refactor for you
to test:

https://github.com/jwrdegoede/linux-sunxi/commits/backlight-refactor-for-arvid

If you can give this a test spin (without any special kernel
commandline options) then that would be great.

>> However, do we know what the other Toshiba's that need this
>> quirk also supports HCI_PANEL_POWER_ON? I obviously can only
>> test the Z830 that I own.
> 
> It seems that all models which need this are all from the same
> generation so I would expect the same fix to work. If I get
> regression reports from users after my cleanup series lands
> I can then take a closer look at the DSDT tables of the
> other models if necessary.

Quick update on this I've taken a look at the DSTD's _BCM method
which is the magic call done by acpi_video on resume which
turns the panel back on and in both a R700 as well as a R830
it ends up doing this:

SMBR (0xFF00, 0x2A, Local0, 0x00, 0xB2)

Which translates to:

HCI_SET HCI_BRIGHTNESS <brightness-level>

Note that in this case brightness-level used by the acpi_video
code is the initial brightness at power-on since acpi_video
is not used to actually control the brightness.

Which makes using HCI_PANEL_POWER_ON a better idea since
that does not touches the brightness.

So I believe that replacing disable_backlight_sysfs_if with
a HCI call by toshiba_acpi on resume should work on all
affected models.

Regards,

Hans