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Message-ID: <820889e8-f004-46a8-9d03-b098ffcdade3@wolfvision.net>
Date: Wed, 29 May 2024 09:01:45 +0200
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH RESEND 1/3] drm/panel: sitronix-st7789v: fix timing for
 jt240mhqs_hwt_ek_e3 panel
To: Jessica Zhang <quic_jesszhan@quicinc.com>,
 Neil Armstrong <neil.armstrong@linaro.org>, Sam Ravnborg <sam@ravnborg.org>,
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
 Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>,
 David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
References: <20240409-bugfix-jt240mhqs_hwt_ek_e3-timing-v1-0-f8351d4a8d4b@wolfvision.net>
 <20240409-bugfix-jt240mhqs_hwt_ek_e3-timing-v1-1-f8351d4a8d4b@wolfvision.net>
 <d10e14ce-b65f-4dbd-8686-bf8c1796ba06@quicinc.com>
From: Gerald Loacker <gerald.loacker@wolfvision.net>
Organization: WolfVision GmbH
In-Reply-To: <d10e14ce-b65f-4dbd-8686-bf8c1796ba06@quicinc.com>
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Hi Jessica,

Am 28.05.2024 um 19:36 schrieb Jessica Zhang:
> 
> 
> On 5/28/2024 1:32 AM, Gerald Loacker wrote:
>> Flickering was observed when using partial mode. Moving the vsync to the
>> same position as used by the default sitronix-st7789v timing resolves
>> this
>> issue.
>>
>> Signed-off-by: Gerald Loacker <gerald.loacker@wolfvision.net>
> 
> Hi Gerald,
> 
> Just wondering, are these new timing values taken from the panel specs?
> If the timing in the original patch was wrong, maybe we need a fixes tag.
> 

Both, the old and the new timing specs, are within the specified range
defined in the data sheet. But as the new values achieve a better result
adding a fixes tag is a good point.

Regards,
Gerald

> Acked-by: Jessica Zhang <quic_jesszhan@quicinc.com>
> 
> Thanks,
> 
> Jessica Zhang
> 
>> ---
>>   drivers/gpu/drm/panel/panel-sitronix-st7789v.c | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/panel/panel-sitronix-st7789v.c
>> b/drivers/gpu/drm/panel/panel-sitronix-st7789v.c
>> index 88e80fe98112..32e5c0348038 100644
>> --- a/drivers/gpu/drm/panel/panel-sitronix-st7789v.c
>> +++ b/drivers/gpu/drm/panel/panel-sitronix-st7789v.c
>> @@ -286,9 +286,9 @@ static const struct drm_display_mode
>> jt240mhqs_hwt_ek_e3_mode = {
>>       .hsync_end = 240 + 28 + 10,
>>       .htotal = 240 + 28 + 10 + 10,
>>       .vdisplay = 280,
>> -    .vsync_start = 280 + 8,
>> -    .vsync_end = 280 + 8 + 4,
>> -    .vtotal = 280 + 8 + 4 + 4,
>> +    .vsync_start = 280 + 48,
>> +    .vsync_end = 280 + 48 + 4,
>> +    .vtotal = 280 + 48 + 4 + 4,
>>       .width_mm = 43,
>>       .height_mm = 37,
>>       .flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC,
>>
>> -- 
>> 2.37.2
>>