According to downstream /and the comment copied from it/ this comparison
should be the other way around.  In other words, when the panel driver
requests to use more slices per packet than what could be sent over this
interface, it is bumped down to only use a single slice per packet (and
strangely not the number of slices that could fit on the interface).

Fixes: 08802f515c3c ("drm/msm/dsi: Add support for DSC configuration")
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 0686c35a6fd4..9bdfa0864cdf 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -855,11 +855,11 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod
 	 */
 	slice_per_intf = DIV_ROUND_UP(hdisplay, dsc->slice_width);
 
-	/* If slice_per_pkt is greater than slice_per_intf
+	/* If slice_count is greater than slice_per_intf
 	 * then default to 1. This can happen during partial
 	 * update.
 	 */
-	if (slice_per_intf > dsc->slice_count)
+	if (dsc->slice_count > slice_per_intf)
 		dsc->slice_count = 1;
 
 	total_bytes_per_intf = dsc->slice_chunk_size * slice_per_intf;
-- 
2.38.1

On 12/13/2022 3:22 PM, Marijn Suijten wrote:
> According to downstream /and the comment copied from it/ this comparison
> should be the other way around.  In other words, when the panel driver
> requests to use more slices per packet than what could be sent over this
> interface, it is bumped down to only use a single slice per packet (and
> strangely not the number of slices that could fit on the interface).
> 
> Fixes: 08802f515c3c ("drm/msm/dsi: Add support for DSC configuration")

Like others have said, with SOB,
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
> ---
>   drivers/gpu/drm/msm/dsi/dsi_host.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 0686c35a6fd4..9bdfa0864cdf 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -855,11 +855,11 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod
>   	 */
>   	slice_per_intf = DIV_ROUND_UP(hdisplay, dsc->slice_width);
>   
> -	/* If slice_per_pkt is greater than slice_per_intf
> +	/* If slice_count is greater than slice_per_intf
>   	 * then default to 1. This can happen during partial
>   	 * update.
>   	 */
> -	if (slice_per_intf > dsc->slice_count)
> +	if (dsc->slice_count > slice_per_intf)
>   		dsc->slice_count = 1;
>   
>   	total_bytes_per_intf = dsc->slice_chunk_size * slice_per_intf;

On 14/12/2022 01:22, Marijn Suijten wrote:
> According to downstream /and the comment copied from it/ this comparison
> should be the other way around.  In other words, when the panel driver
> requests to use more slices per packet than what could be sent over this
> interface, it is bumped down to only use a single slice per packet (and
> strangely not the number of slices that could fit on the interface).
> 
> Fixes: 08802f515c3c ("drm/msm/dsi: Add support for DSC configuration")
> ---
>   drivers/gpu/drm/msm/dsi/dsi_host.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)

With SoB in place:
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

-- 
With best wishes
Dmitry

On 14.12.2022 00:22, Marijn Suijten wrote:
> According to downstream /and the comment copied from it/ this comparison
> should be the other way around.  In other words, when the panel driver
> requests to use more slices per packet than what could be sent over this
> interface, it is bumped down to only use a single slice per packet (and
> strangely not the number of slices that could fit on the interface).
> 
> Fixes: 08802f515c3c ("drm/msm/dsi: Add support for DSC configuration")
> ---
Missing s-o-b

>  drivers/gpu/drm/msm/dsi/dsi_host.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 0686c35a6fd4..9bdfa0864cdf 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -855,11 +855,11 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod
>  	 */
>  	slice_per_intf = DIV_ROUND_UP(hdisplay, dsc->slice_width);
>  
> -	/* If slice_per_pkt is greater than slice_per_intf
> +	/* If slice_count is greater than slice_per_intf
>  	 * then default to 1. This can happen during partial
>  	 * update.
>  	 */
> -	if (slice_per_intf > dsc->slice_count)
> +	if (dsc->slice_count > slice_per_intf)
>  		dsc->slice_count = 1;
>  
>  	total_bytes_per_intf = dsc->slice_chunk_size * slice_per_intf;

On 2022-12-14 01:02:14, Konrad Dybcio wrote:
> 
> 
> On 14.12.2022 00:22, Marijn Suijten wrote:
> > According to downstream /and the comment copied from it/ this comparison
> > should be the other way around.  In other words, when the panel driver
> > requests to use more slices per packet than what could be sent over this
> > interface, it is bumped down to only use a single slice per packet (and
> > strangely not the number of slices that could fit on the interface).
> > 
> > Fixes: 08802f515c3c ("drm/msm/dsi: Add support for DSC configuration")

Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>

> > ---
> Missing s-o-b

Thanks for catching, checkpatch would've pointed this out (in addition
to a typo in the cover letter) if I had ran it.

> >  drivers/gpu/drm/msm/dsi/dsi_host.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> > index 0686c35a6fd4..9bdfa0864cdf 100644
> > --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> > +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> > @@ -855,11 +855,11 @@ static void dsi_update_dsc_timing(struct msm_dsi_host *msm_host, bool is_cmd_mod
> >  	 */
> >  	slice_per_intf = DIV_ROUND_UP(hdisplay, dsc->slice_width);
> >  
> > -	/* If slice_per_pkt is greater than slice_per_intf
> > +	/* If slice_count is greater than slice_per_intf
> >  	 * then default to 1. This can happen during partial
> >  	 * update.
> >  	 */
> > -	if (slice_per_intf > dsc->slice_count)
> > +	if (dsc->slice_count > slice_per_intf)
> >  		dsc->slice_count = 1;
> >  
> >  	total_bytes_per_intf = dsc->slice_chunk_size * slice_per_intf;