From: Doug Anderson <dianders@google.com>
To: Cong Yang <yangcong5@huaqin.corp-partner.google.com>
Cc: sam@ravnborg.org, neil.armstrong@linaro.org, daniel@ffwll.ch,
hsinyi@google.com, linus.walleij@linaro.org, swboyd@chromium.org,
airlied@gmail.com, catalin.marinas@arm.com, will@kernel.org,
dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [v4 2/3] drm/panel: ili9882t: Avoid blurred screen from fast sleep
Date: Fri, 13 Oct 2023 14:43:12 -0700 [thread overview]
Message-ID: <CAD=FV=UVP22ANJD5xEB6MRHCDjXN6SZhQWQshPxwhi51YRkEjQ@mail.gmail.com> (raw)
In-Reply-To: <20231013091844.804310-3-yangcong5@huaqin.corp-partner.google.com>
Hi,
On Fri, Oct 13, 2023 at 2:19 AM Cong Yang
<yangcong5@huaqin.corp-partner.google.com> wrote:
>
> At present, we have found that there may be a problem of blurred
> screen during fast sleep/resume. The direct cause of the blurred
> screen is that the IC does not receive 0x28/0x10. Because of the
> particularity of the IC, before the panel enters sleep hid must
> stop scanning, as i2c_hid_core_suspend before ili9882t_disable.
> If move the ili9882t_enter_sleep_mode function to ili9882t_unprepare,
> touch reset will pull low before panel entersleep, which does not meet
> the timing requirements.. So in order to solve this problem, the IC
> can handle it through the exception mechanism when it cannot receive
> 0x28/0x10 command. Handling exceptions requires a reset 50ms delay.
> Refer to vendor detailed analysis [1].
>
> Ilitek vendor also suggested switching the page before entering sleep to
> avoid panel IC not receiving 0x28/0x10 command.
>
> Note: 0x28 is display off, 0x10 is sleep in.
>
> [1]: https://github.com/ILITEK-LoganLin/Document/tree/main/ILITEK_Power_Sequence
>
> Signed-off-by: Cong Yang <yangcong5@huaqin.corp-partner.google.com>
> ---
> drivers/gpu/drm/panel/panel-ilitek-ili9882t.c | 22 ++++++++++++++++++-
> 1 file changed, 21 insertions(+), 1 deletion(-)
As talked about in response to the previous version [1], we can work
to see if we can improve the sequencing. However, for now this seems
fine.
Reviewed-by: Douglas Anderson <dianders@chromium.org>
[1] https://lore.kernel.org/r/CAD=FV=W_LT9mPYKjaKP3OvUDeNpsZxkhVN9NP_hQ+Es6Fe3dVw@mail.gmail.com
next parent reply other threads:[~2023-10-13 21:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20231013091844.804310-1-yangcong5@huaqin.corp-partner.google.com>
[not found] ` <20231013091844.804310-3-yangcong5@huaqin.corp-partner.google.com>
2023-10-13 21:43 ` Doug Anderson [this message]
2023-10-19 21:50 ` [v4 2/3] drm/panel: ili9882t: Avoid blurred screen from fast sleep Doug Anderson
2023-10-13 21:44 ` [v4 0/3] Break out as separate driver from boe-tv101wum-nl6 panel driver Doug Anderson
[not found] ` <20231013091844.804310-2-yangcong5@huaqin.corp-partner.google.com>
2023-10-19 21:49 ` [v4 1/3] drm/panel: ili9882t: Break out as separate driver Doug Anderson
2023-10-20 11:11 ` Linus Walleij
[not found] ` <20231013091844.804310-4-yangcong5@huaqin.corp-partner.google.com>
2023-10-19 21:50 ` [v4 3/3] arm64: defconfig: Enable ILITEK_ILI9882T panel Doug Anderson
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