On 29/07/2025 07:44, Brigham Campbell wrote:
Fix bug in nt35560_set_brightness() which causes the function to
erroneously report an error. mipi_dsi_dcs_write() returns either a
negative value when an error occurred or a positive number of bytes
written when no error occurred. The buggy code reports an error under
either condition.

Fixes: 7835ed6a9e86 ("drm/panel-sony-acx424akp: Modernize backlight handling")
Signed-off-by: Brigham Campbell <m...@brighamcampbell.com>
---
  drivers/gpu/drm/panel/panel-novatek-nt35560.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panel/panel-novatek-nt35560.c 
b/drivers/gpu/drm/panel/panel-novatek-nt35560.c
index 98f0782c8411..17898a29efe8 100644
--- a/drivers/gpu/drm/panel/panel-novatek-nt35560.c
+++ b/drivers/gpu/drm/panel/panel-novatek-nt35560.c
@@ -161,7 +161,7 @@ static int nt35560_set_brightness(struct backlight_device 
*bl)
                par = 0x00;
                ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_WRITE_CONTROL_DISPLAY,
                                         &par, 1);
-               if (ret) {
+               if (ret < 0) {
                        dev_err(nt->dev, "failed to disable display backlight 
(%d)\n", ret);
                        return ret;
                }

Reviewed-by: Neil Armstrong <neil.armstr...@linaro.org>

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