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Subject: Re: [PATCH 5/6] drm: vkms: Prepare `vkms_wb_encoder_atomic_check` to
 accept multiple formats
To:     Thomas Zimmermann <tzimmermann@suse.de>,
        rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com
Cc:     hamohammed.sa@gmail.com, daniel@ffwll.ch, airlied@linux.ie,
        contact@emersion.fr, leandro.ribeiro@collabora.com,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        lkcamp@lists.libreplanetbr.org
References: <20211005201637.58563-1-igormtorrente@gmail.com>
 <20211005201637.58563-6-igormtorrente@gmail.com>
 <5507450a-eb69-b24c-9f43-a1780dafbfa9@suse.de>
From:   Igor Matheus Andrade Torrente <igormtorrente@gmail.com>
Message-ID: <e9cbdad7-416a-65fe-eb50-1cbb42a01e7b@gmail.com>
Date:   Mon, 18 Oct 2021 14:41:33 -0300
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Hello,

On 10/18/21 7:14 AM, Thomas Zimmermann wrote:
> Hi
> 
> Am 05.10.21 um 22:16 schrieb Igor Matheus Andrade Torrente:
>> Currently, the vkms atomic check only goes through the first position of
>> the `vkms_wb_formats` vector.
>>
>> This change prepares the atomic_check to check the entire vector.
>>
>> Signed-off-by: Igor Matheus Andrade Torrente <igormtorrente@gmail.com>
>> ---
>>   drivers/gpu/drm/vkms/vkms_writeback.c | 11 ++++++++++-
>>   1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c 
>> b/drivers/gpu/drm/vkms/vkms_writeback.c
>> index 5a3e12f105dc..56978f499203 100644
>> --- a/drivers/gpu/drm/vkms/vkms_writeback.c
>> +++ b/drivers/gpu/drm/vkms/vkms_writeback.c
>> @@ -30,6 +30,8 @@ static int vkms_wb_encoder_atomic_check(struct 
>> drm_encoder *encoder,
>>   {
>>       struct drm_framebuffer *fb;
>>       const struct drm_display_mode *mode = &crtc_state->mode;
>> +    bool format_supported = false;
>> +    int i;
>>       if (!conn_state->writeback_job || !conn_state->writeback_job->fb)
>>           return 0;
>> @@ -41,7 +43,14 @@ static int vkms_wb_encoder_atomic_check(struct 
>> drm_encoder *encoder,
>>           return -EINVAL;
>>       }
>> -    if (fb->format->format != vkms_wb_formats[0]) {
>> +    for (i = 0; i < ARRAY_SIZE(vkms_wb_formats); i++) {
>> +        if (fb->format->format == vkms_wb_formats[i]) {
>> +            format_supported = true;
>> +            break;
>> +        }
>> +    }
> 
> At a minimum, this loop should be in a helper function. But more 
> generally, I'm surprised that this isn't already covered by the DRM's 
> atomic helpers.

Ok, I can wrap it in a new function.

AFAIK the DRM doesn't cover it. But I may be wrong...

> 
> Best regards
> Thomas
> 
>> +
>> +    if (!format_supported) {
>>           DRM_DEBUG_KMS("Invalid pixel format %p4cc\n",
>>                     &fb->format->format);
>>           return -EINVAL;
>>
>