Re: [PATCH v3 5/6] drm/display: Add slice_per_pkt for dsc
On 2024-04-08 17:58:29, Jun Nie wrote:
> Dmitry Baryshkov 于2024年4月3日周三 17:41写道：
> >
> > On Wed, 3 Apr 2024 at 12:11, Jun Nie wrote:
> > >
> > > Add variable for slice number of a DSC compression bit stream packet.
> > > Its value shall be specified in panel driver, or default value can be set
> > > in display controller driver if panel driver does not set it.
> >
> > This is not a part of the standard. Please justify it.
>
> Right, I read the standard but did not find any details of packet description.
> Looks like msm silicon support tuning of number of slice packing per
> downstream
> code.
> The slice_per_pkt can be set in the downstream msm device tree. And I test the
> values 1 and 2 on vtdr6130 panel and both work. So I guess this is related to
> performance or something like that. I will have more test with different panel
> to check the impact.
> drivers/gpu/drm/panel/panel-raydium-rm692e5.c also mentions to pass new value
> to slice_per_pkt.
>
> Hi Konrad,
> Do you remember why value 2 is TODO for slice_per_pkt for panel rm692e5?
Hi Jun,
I think I should indirectly answer that question, as I indirectly via "the"
MDSS panel generator place that comment there based on the suggested downstream
value:
https://github.com/msm8916-mainline/linux-mdss-dsi-panel-driver-generator/commit/5c82e613d987d05feca423412f6de625f9c99bae#diff-dba3766d7cec900b8de500f888c64a392cd9780f9baf00aae7e3f87a7d3fefc4R458
So I don't think Konrad's answer will be any different than "that's what
downstream does, and that's what the generator put there".
---
I was fairly certain that it used for performance reasons, but panels were found
(e.g. on the FairPhone 5) that don't seem to function without combining multiple
(2) slices in one packet at all?
- Marijn
> > > Signed-off-by: Jun Nie
> > > ---
> > > include/drm/display/drm_dsc.h | 4
> > > 1 file changed, 4 insertions(+)
> > >
> > > diff --git a/include/drm/display/drm_dsc.h b/include/drm/display/drm_dsc.h
> > > index bc90273d06a6..4fac0a2746ae 100644
> > > --- a/include/drm/display/drm_dsc.h
> > > +++ b/include/drm/display/drm_dsc.h
> > > @@ -82,6 +82,10 @@ struct drm_dsc_config {
> > > * @bits_per_component: Bits per component to code (8/10/12)
> > > */
> > > u8 bits_per_component;
> > > + /**
> > > +* @slice_per_pkt: slice number per DSC bit stream packet
> > > +*/
> > > + u8 slice_per_pkt;
> > > /**
> > > * @convert_rgb:
> > > * Flag to indicate if RGB - YCoCg conversion is needed
> > >
> > > --
> > > 2.34.1
> > >
> >
> >
> > --
> > With best wishes
> > Dmitry
Re: [PATCH v3 5/6] drm/display: Add slice_per_pkt for dsc
Dmitry Baryshkov 于2024年4月3日周三 17:41写道：
>
> On Wed, 3 Apr 2024 at 12:11, Jun Nie wrote:
> >
> > Add variable for slice number of a DSC compression bit stream packet.
> > Its value shall be specified in panel driver, or default value can be set
> > in display controller driver if panel driver does not set it.
>
> This is not a part of the standard. Please justify it.
Right, I read the standard but did not find any details of packet description.
Looks like msm silicon support tuning of number of slice packing per downstream
code.
The slice_per_pkt can be set in the downstream msm device tree. And I test the
values 1 and 2 on vtdr6130 panel and both work. So I guess this is related to
performance or something like that. I will have more test with different panel
to check the impact.
drivers/gpu/drm/panel/panel-raydium-rm692e5.c also mentions to pass new value
to slice_per_pkt.
Hi Konrad,
Do you remember why value 2 is TODO for slice_per_pkt for panel rm692e5?
>
> >
> > Signed-off-by: Jun Nie
> > ---
> > include/drm/display/drm_dsc.h | 4
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/include/drm/display/drm_dsc.h b/include/drm/display/drm_dsc.h
> > index bc90273d06a6..4fac0a2746ae 100644
> > --- a/include/drm/display/drm_dsc.h
> > +++ b/include/drm/display/drm_dsc.h
> > @@ -82,6 +82,10 @@ struct drm_dsc_config {
> > * @bits_per_component: Bits per component to code (8/10/12)
> > */
> > u8 bits_per_component;
> > + /**
> > +* @slice_per_pkt: slice number per DSC bit stream packet
> > +*/
> > + u8 slice_per_pkt;
> > /**
> > * @convert_rgb:
> > * Flag to indicate if RGB - YCoCg conversion is needed
> >
> > --
> > 2.34.1
> >
>
>
> --
> With best wishes
> Dmitry
Re: [PATCH v3 5/6] drm/display: Add slice_per_pkt for dsc
On Wed, 3 Apr 2024 at 12:11, Jun Nie wrote:
>
> Add variable for slice number of a DSC compression bit stream packet.
> Its value shall be specified in panel driver, or default value can be set
> in display controller driver if panel driver does not set it.
This is not a part of the standard. Please justify it.
>
> Signed-off-by: Jun Nie
> ---
> include/drm/display/drm_dsc.h | 4
> 1 file changed, 4 insertions(+)
>
> diff --git a/include/drm/display/drm_dsc.h b/include/drm/display/drm_dsc.h
> index bc90273d06a6..4fac0a2746ae 100644
> --- a/include/drm/display/drm_dsc.h
> +++ b/include/drm/display/drm_dsc.h
> @@ -82,6 +82,10 @@ struct drm_dsc_config {
> * @bits_per_component: Bits per component to code (8/10/12)
> */
> u8 bits_per_component;
> + /**
> +* @slice_per_pkt: slice number per DSC bit stream packet
> +*/
> + u8 slice_per_pkt;
> /**
> * @convert_rgb:
> * Flag to indicate if RGB - YCoCg conversion is needed
>
> --
> 2.34.1
>
--
With best wishes
Dmitry
[PATCH v3 5/6] drm/display: Add slice_per_pkt for dsc
Add variable for slice number of a DSC compression bit stream packet.
Its value shall be specified in panel driver, or default value can be set
in display controller driver if panel driver does not set it.
Signed-off-by: Jun Nie
---
include/drm/display/drm_dsc.h | 4
1 file changed, 4 insertions(+)
diff --git a/include/drm/display/drm_dsc.h b/include/drm/display/drm_dsc.h
index bc90273d06a6..4fac0a2746ae 100644
--- a/include/drm/display/drm_dsc.h
+++ b/include/drm/display/drm_dsc.h
@@ -82,6 +82,10 @@ struct drm_dsc_config {
* @bits_per_component: Bits per component to code (8/10/12)
*/
u8 bits_per_component;
+ /**
+* @slice_per_pkt: slice number per DSC bit stream packet
+*/
+ u8 slice_per_pkt;
/**
* @convert_rgb:
* Flag to indicate if RGB - YCoCg conversion is needed
--
2.34.1
