On Tue, 19 Aug 2025, Suraj Kandpal <[email protected]> wrote:
> pwm_level_max maybe 0 we do throw a warning but move ahead with
> execution which may later cause a /0 error.
This is not supposed to happen, so don't overcomplicate.
if (warn on)
return
>
> Signed-off-by: Suraj Kandpal <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_backlight.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c
> b/drivers/gpu/drm/i915/display/intel_backlight.c
> index e007380e9a63..d0e9de8ab834 100644
> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
> @@ -234,6 +234,7 @@ static void i9xx_set_backlight(const struct
> drm_connector_state *conn_state, u32
> struct intel_connector *connector =
> to_intel_connector(conn_state->connector);
> struct intel_display *display = to_intel_display(connector);
> struct intel_panel *panel = &connector->panel;
> + u32 max_level = panel->backlight.pwm_level_max ?: 1;
> u32 tmp, mask;
>
> drm_WARN_ON(display->drm, panel->backlight.pwm_level_max == 0);
> @@ -242,7 +243,7 @@ static void i9xx_set_backlight(const struct
> drm_connector_state *conn_state, u32
> struct pci_dev *pdev = to_pci_dev(display->drm->dev);
> u8 lbpc;
>
> - lbpc = level * 0xfe / panel->backlight.pwm_level_max + 1;
> + lbpc = level * 0xfe / max_level + 1;
> level /= lbpc;
> pci_write_config_byte(pdev, LBPC, lbpc);
> }
--
Jani Nikula, Intel
