From: Jessica Zhang <quic_jesszhan@quicinc.com>
To: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
Marijn Suijten <marijn.suijten@somainline.org>,
Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
<linux-arm-msm@vger.kernel.org>,
<freedreno@lists.freedesktop.org>,
<dri-devel@lists.freedesktop.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/3] drm/msm/dpu: Set DATABUS_WIDEN on command mode encoders
Date: Tue, 20 Jun 2023 14:38:34 -0700 [thread overview]
Message-ID: <f14f2c31-38c2-0600-3a29-17e83afececf@quicinc.com> (raw)
In-Reply-To: <81a5e241-ec82-7414-8752-4ce3cb084959@linaro.org>
On 6/16/2023 5:35 PM, Dmitry Baryshkov wrote:
> On 17/06/2023 00:54, Marijn Suijten wrote:
>> On 2023-06-16 14:18:39, Abhinav Kumar wrote:
>>>
>>>
>>> On 6/14/2023 12:56 AM, Dmitry Baryshkov wrote:
>>>> On 14/06/2023 04:57, Jessica Zhang wrote:
>>>>> Add a DPU INTF op to set the DATABUS_WIDEN register to enable the
>>>>> databus-widen mode datapath.
>>>>>
>>>>> Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
>>>>> ---
>>>>> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c | 3 +++
>>>>> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c | 12
>>>>> ++++++++++++
>>>>> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h | 3 +++
>>>>> 3 files changed, 18 insertions(+)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
>>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
>>>>> index b856c6286c85..124ba96bebda 100644
>>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
>>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
>>>>> @@ -70,6 +70,9 @@ static void _dpu_encoder_phys_cmd_update_intf_cfg(
>>>>> if (intf_cfg.dsc != 0 &&
>>>>> phys_enc->hw_intf->ops.enable_compression)
>>>>>
>>>>> phys_enc->hw_intf->ops.enable_compression(phys_enc->hw_intf);
>>>>> +
>>>>> + if (phys_enc->hw_intf->ops.enable_widebus)
>>>>> + phys_enc->hw_intf->ops.enable_widebus(phys_enc->hw_intf);
>>>>
>>>> No. Please provide a single function which takes necessary
>>>> configuration, including compression and wide_bus_enable.
>>>>
>>>
>>> There are two ways to look at this. Your point is coming from the
>>> perspective that its programming the same register but just a different
>>> bit. But that will also make it a bit confusing.
>
> My point is to have a high-level function that configures the INTF for
> the CMD mode. This way it can take a structure with necessary
> configuration bits.
Hi Dmitry,
After discussing this approach with Abhinav, we still have a few
questions about it:
Currently, only 3 of the 32 bits for INTF_CONFIG2 are being used (the
rest are reserved with no plans of being programmed in the future). Does
this still justify the use of a struct to pass in the necessary
configuration?
In addition, it seems that video mode does all its INTF_CONFIG2
configuration separately in dpu_hw_intf_setup_timing_engine(). If we
have a generic set_intf_config2() op, it might be good to have it as
part of a larger cleanup where we have both video and command mode use
the generic op. What are your thoughts on this?
Thanks,
Jessica Zhang
>
>>>
>>> So lets say the function is called intf_cfg2_xxx(..., bool widebus, bool
>>> data_compress)
>>>
>>> Now for the caller who wants to just enable widebus this will be
>>>
>>> intf_cfg2_xxx(....., true, false)
>>>
>>> if we want to do both
>>>
>>> intf_cfg2_xxx(...., true, true)
>>>
>>> the last one where we want to do just data_compress(highly unlikely and
>>> not recommended)
>>>
>>> intf_cfg2_xxx(...., false, true)
>>>
>>> Now someone looking at the code will have to go and find out what each
>>> bool is.
>>>
>>> Whereas with separate ops, its kind of implicit.
>>
>> That's why you never pass bools as function argument (edge-case if it is
>> the only argument, and its meaning becomes clear from the function
>> name). Use enumerations anywhere else.
>>
>> - Marijn
>>
>>>
>>> For that reason, I dont think this patch is bad at all.
>
> --
> With best wishes
> Dmitry
>
next prev parent reply other threads:[~2023-06-20 21:39 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-14 1:57 [PATCH 0/3] Add support for databus widen mode Jessica Zhang
2023-06-14 1:57 ` [PATCH 1/3] drm/msm/dpu: Add DPU_INTF_DATABUS_WIDEN feature flag for DPU >= 5.0 Jessica Zhang
2023-06-14 7:50 ` Dmitry Baryshkov
2023-06-14 11:42 ` Marijn Suijten
2023-06-14 12:01 ` Dmitry Baryshkov
2023-06-14 12:23 ` Marijn Suijten
2023-06-14 19:35 ` Abhinav Kumar
2023-06-14 19:54 ` Abhinav Kumar
2023-06-14 20:39 ` [Freedreno] " Abhinav Kumar
2023-06-14 20:43 ` Dmitry Baryshkov
2023-06-16 21:10 ` Abhinav Kumar
2023-06-17 0:37 ` Dmitry Baryshkov
2023-06-20 21:37 ` Jessica Zhang
2023-06-20 22:11 ` Dmitry Baryshkov
2023-06-20 23:37 ` Jessica Zhang
2023-06-14 21:41 ` Marijn Suijten
2023-06-16 21:13 ` Abhinav Kumar
2023-06-16 21:58 ` Marijn Suijten
2023-06-14 22:49 ` Marijn Suijten
2023-06-16 21:06 ` Abhinav Kumar
2023-06-16 22:00 ` Marijn Suijten
2023-06-14 1:57 ` [PATCH 2/3] drm/msm/dpu: Set DATABUS_WIDEN on command mode encoders Jessica Zhang
2023-06-14 7:56 ` Dmitry Baryshkov
2023-06-16 21:18 ` Abhinav Kumar
2023-06-16 21:54 ` Marijn Suijten
2023-06-17 0:35 ` Dmitry Baryshkov
2023-06-20 21:38 ` Jessica Zhang [this message]
2023-06-20 22:10 ` Dmitry Baryshkov
2023-06-21 15:17 ` Marijn Suijten
2023-06-21 16:36 ` Dmitry Baryshkov
2023-06-21 19:00 ` Marijn Suijten
2023-06-21 23:01 ` Abhinav Kumar
2023-06-21 23:46 ` Dmitry Baryshkov
2023-06-22 22:37 ` Abhinav Kumar
2023-06-22 23:14 ` Dmitry Baryshkov
2023-06-22 23:37 ` [Freedreno] " Abhinav Kumar
2023-06-29 17:26 ` Abhinav Kumar
2023-06-29 17:37 ` Jessica Zhang
2023-06-14 1:57 ` [PATCH 3/3] drm/msm/dsi: Enable DATABUS_WIDEN for DSI command mode Jessica Zhang
2023-06-14 7:49 ` Dmitry Baryshkov
2023-06-14 10:03 ` Marijn Suijten
2023-06-22 23:04 ` Abhinav Kumar
2023-06-23 7:02 ` Marijn Suijten
2023-06-16 21:23 ` Abhinav Kumar
2023-06-14 9:56 ` Marijn Suijten
2023-06-23 0:01 ` [Freedreno] " Abhinav Kumar
2023-06-23 0:41 ` Dmitry Baryshkov
2023-06-23 7:19 ` Marijn Suijten
2023-06-23 17:29 ` Abhinav Kumar
2023-06-23 20:14 ` Marijn Suijten
2023-06-23 20:34 ` Abhinav Kumar
2023-06-23 21:33 ` Marijn Suijten
2023-06-23 21:47 ` Abhinav Kumar
2023-06-14 10:09 ` [PATCH 0/3] Add support for databus widen mode Marijn Suijten
2023-06-16 11:30 ` Dmitry Baryshkov
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