diff mbox series

[v2,2/2] drm/msm/dsi: fix 32-bit signed integer extension in pclk_rate calculation

Message ID 20241007050157.26855-2-jonathan@marek.ca
State Accepted
Commit 358b762400bd94db2a14a72dfcef74c7da6bd845
Headers show
Series [v2,1/2] drm/msm/dsi: improve/fix dsc pclk calculation | expand

Commit Message

Jonathan Marek Oct. 7, 2024, 5:01 a.m. UTC
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: c4d8cfe516dc ("drm/msm/dsi: add implementation for helper functions")
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Abhinav Kumar Oct. 14, 2024, 7:30 p.m. UTC | #1
On 10/6/2024 10:01 PM, 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: c4d8cfe516dc ("drm/msm/dsi: add implementation for helper functions")
> Signed-off-by: Jonathan Marek <jonathan@marek.ca>
> ---
>   drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
diff mbox series

Patch

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);