* [PATCH 2/2] drm/msm/dsi: fix 32-bit signed integer extension in pclk_rate calculation
2024-10-05 14:38 [PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation Jonathan Marek
@ 2024-10-05 14:38 ` Jonathan Marek
2024-10-06 17:32 ` Dmitry Baryshkov
2024-10-05 16:31 ` [PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation Konrad Dybcio
2024-10-06 17:32 ` Dmitry Baryshkov
2 siblings, 1 reply; 6+ messages in thread
From: Jonathan Marek @ 2024-10-05 14:38 UTC (permalink / raw)
To: freedreno
Cc: Rob Clark, Abhinav Kumar, Dmitry Baryshkov, Sean Paul,
Marijn Suijten, David Airlie, Simona Vetter, Jessica Zhang,
Konrad Dybcio, open list:DRM DRIVER for Qualcomm display hardware,
open list:DRM DRIVER for Qualcomm display hardware, open list
When (mode->clock * 1000) is larger than (1<<31), int to unsigned long
conversion will sign extend the int to 64 bits and the pclk_rate value
will be incorrect.
Fix this by making the result of the multiplication unsigned.
Note that above (1<<32) would still be broken and require more changes, but
its unlikely anyone will need that anytime soon.
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
---
drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 1205aa398e445..a98d24b7cb00b 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -550,7 +550,7 @@ static unsigned long dsi_get_pclk_rate(const struct drm_display_mode *mode,
{
unsigned long pclk_rate;
- pclk_rate = mode->clock * 1000;
+ pclk_rate = mode->clock * 1000u;
if (dsc)
pclk_rate = dsi_adjust_pclk_for_compression(mode, dsc);
--
2.45.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH 2/2] drm/msm/dsi: fix 32-bit signed integer extension in pclk_rate calculation
2024-10-05 14:38 ` [PATCH 2/2] drm/msm/dsi: fix 32-bit signed integer extension in pclk_rate calculation Jonathan Marek
@ 2024-10-06 17:32 ` Dmitry Baryshkov
0 siblings, 0 replies; 6+ messages in thread
From: Dmitry Baryshkov @ 2024-10-06 17:32 UTC (permalink / raw)
To: Jonathan Marek
Cc: freedreno, Rob Clark, Abhinav Kumar, Sean Paul, Marijn Suijten,
David Airlie, Simona Vetter, Jessica Zhang, Konrad Dybcio,
open list:DRM DRIVER for Qualcomm display hardware,
open list:DRM DRIVER for Qualcomm display hardware, open list
On Sat, Oct 05, 2024 at 10:38:10AM GMT, Jonathan Marek wrote:
> When (mode->clock * 1000) is larger than (1<<31), int to unsigned long
> conversion will sign extend the int to 64 bits and the pclk_rate value
> will be incorrect.
>
> Fix this by making the result of the multiplication unsigned.
>
> Note that above (1<<32) would still be broken and require more changes, but
> its unlikely anyone will need that anytime soon.
>
Fixes?
> Signed-off-by: Jonathan Marek <jonathan@marek.ca>
> ---
> drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 1205aa398e445..a98d24b7cb00b 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -550,7 +550,7 @@ static unsigned long dsi_get_pclk_rate(const struct drm_display_mode *mode,
> {
> unsigned long pclk_rate;
>
> - pclk_rate = mode->clock * 1000;
> + pclk_rate = mode->clock * 1000u;
>
> if (dsc)
> pclk_rate = dsi_adjust_pclk_for_compression(mode, dsc);
> --
> 2.45.1
>
--
With best wishes
Dmitry
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation
2024-10-05 14:38 [PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation Jonathan Marek
2024-10-05 14:38 ` [PATCH 2/2] drm/msm/dsi: fix 32-bit signed integer extension in pclk_rate calculation Jonathan Marek
@ 2024-10-05 16:31 ` Konrad Dybcio
2024-10-05 16:55 ` Jonathan Marek
2024-10-06 17:32 ` Dmitry Baryshkov
2 siblings, 1 reply; 6+ messages in thread
From: Konrad Dybcio @ 2024-10-05 16:31 UTC (permalink / raw)
To: Jonathan Marek, freedreno
Cc: Rob Clark, Abhinav Kumar, Dmitry Baryshkov, Sean Paul,
Marijn Suijten, David Airlie, Simona Vetter, Jessica Zhang,
Konrad Dybcio, open list:DRM DRIVER for Qualcomm display hardware,
open list:DRM DRIVER for Qualcomm display hardware, open list
On 5.10.2024 4:38 PM, Jonathan Marek wrote:
> drm_mode_vrefresh() can introduce a large rounding error, avoid it.
>
> Signed-off-by: Jonathan Marek <jonathan@marek.ca>
> ---
> drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 185d7de0bf376..1205aa398e445 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -542,7 +542,7 @@ static unsigned long dsi_adjust_pclk_for_compression(const struct drm_display_mo
>
> int new_htotal = mode->htotal - mode->hdisplay + new_hdisplay;
>
> - return new_htotal * mode->vtotal * drm_mode_vrefresh(mode);
> + return mult_frac(mode->clock * 1000u, new_htotal, mode->htotal);
This seems to ignore mult/div by two on certain mode flags.. is that
intended?
Konrad
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation
2024-10-05 16:31 ` [PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation Konrad Dybcio
@ 2024-10-05 16:55 ` Jonathan Marek
0 siblings, 0 replies; 6+ messages in thread
From: Jonathan Marek @ 2024-10-05 16:55 UTC (permalink / raw)
To: Konrad Dybcio, freedreno
Cc: Rob Clark, Abhinav Kumar, Dmitry Baryshkov, Sean Paul,
Marijn Suijten, David Airlie, Simona Vetter, Jessica Zhang,
Konrad Dybcio, open list:DRM DRIVER for Qualcomm display hardware,
open list:DRM DRIVER for Qualcomm display hardware, open list
On 10/5/24 12:31 PM, Konrad Dybcio wrote:
> On 5.10.2024 4:38 PM, Jonathan Marek wrote:
>> drm_mode_vrefresh() can introduce a large rounding error, avoid it.
>>
>> Signed-off-by: Jonathan Marek <jonathan@marek.ca>
>> ---
>> drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
>> index 185d7de0bf376..1205aa398e445 100644
>> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
>> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
>> @@ -542,7 +542,7 @@ static unsigned long dsi_adjust_pclk_for_compression(const struct drm_display_mo
>>
>> int new_htotal = mode->htotal - mode->hdisplay + new_hdisplay;
>>
>> - return new_htotal * mode->vtotal * drm_mode_vrefresh(mode);
>> + return mult_frac(mode->clock * 1000u, new_htotal, mode->htotal);
>
> This seems to ignore mult/div by two on certain mode flags.. is that
> intended?
>
> Konrad
>
It is intended - those flags are not relevant to DSI panels, and DSC
pclk adjustment is only about how DSC affects htotal.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation
2024-10-05 14:38 [PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation Jonathan Marek
2024-10-05 14:38 ` [PATCH 2/2] drm/msm/dsi: fix 32-bit signed integer extension in pclk_rate calculation Jonathan Marek
2024-10-05 16:31 ` [PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation Konrad Dybcio
@ 2024-10-06 17:32 ` Dmitry Baryshkov
2 siblings, 0 replies; 6+ messages in thread
From: Dmitry Baryshkov @ 2024-10-06 17:32 UTC (permalink / raw)
To: Jonathan Marek
Cc: freedreno, Rob Clark, Abhinav Kumar, Sean Paul, Marijn Suijten,
David Airlie, Simona Vetter, Jessica Zhang, Konrad Dybcio,
open list:DRM DRIVER for Qualcomm display hardware,
open list:DRM DRIVER for Qualcomm display hardware, open list
On Sat, Oct 05, 2024 at 10:38:09AM GMT, Jonathan Marek wrote:
> drm_mode_vrefresh() can introduce a large rounding error, avoid it.
>
Fixes?
> Signed-off-by: Jonathan Marek <jonathan@marek.ca>
> ---
> drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 185d7de0bf376..1205aa398e445 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -542,7 +542,7 @@ static unsigned long dsi_adjust_pclk_for_compression(const struct drm_display_mo
>
> int new_htotal = mode->htotal - mode->hdisplay + new_hdisplay;
>
> - return new_htotal * mode->vtotal * drm_mode_vrefresh(mode);
> + return mult_frac(mode->clock * 1000u, new_htotal, mode->htotal);
> }
>
> static unsigned long dsi_get_pclk_rate(const struct drm_display_mode *mode,
> --
> 2.45.1
>
--
With best wishes
Dmitry
^ permalink raw reply [flat|nested] 6+ messages in thread