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Wed, 30 Jul 2025 20:23:50 -0700 (PDT) From: Brigham Campbell To: maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch, linus.walleij@linaro.org, neil.armstrong@linaro.org, jessica.zhang@oss.qualcomm.com, sam@ravnborg.org Cc: dianders@chromium.org, skhan@linuxfoundation.org, linux-kernel-mentees@lists.linux.dev, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Brigham Campbell Subject: [PATCH v4 1/3] drm/panel: novatek-nt35560: Fix invalid return value Date: Wed, 30 Jul 2025 21:23:41 -0600 Message-ID: <20250731032343.1258366-2-me@brighamcampbell.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250731032343.1258366-1-me@brighamcampbell.com> References: <20250731032343.1258366-1-me@brighamcampbell.com> Precedence: bulk X-Mailing-List: linux-kernel-mentees@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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: 8152c2bfd780 ("drm/panel: Add driver for Sony ACX424AKP panel") Reviewed-by: Douglas Anderson Reviewed-by: Neil Armstrong Signed-off-by: Brigham Campbell --- 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; } -- 2.50.1