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

From: Jonathan Marek
Date: Sat Oct 05 2024 - 10:43:46 EST


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@xxxxxxxx>
---
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