Re: [PATCH] backlight: pwm_bl: print errno for probe errors

Hello Martin,

On Thu, Aug 01, 2024 at 09:52:01AM +0000, Kepplinger-Novakovic Martin wrote:

Am Donnerstag, dem 01.08.2024 um 11:26 +0200 schrieb Uwe Kleine-König:

quoted

On Thu, Aug 01, 2024 at 11:12:55AM +0200, Martin Kepplinger-Novaković
wrote:

quoted

diff --git a/drivers/video/backlight/pwm_bl.c

b/drivers/video/backlight/pwm_bl.c
index f1005bd0c41e3..cc7e7af71891f 100644

--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c

@@ -502,7 +502,8 @@ static int pwm_backlight_probe(struct

platform_device *pdev)
                                                  GPIOD_ASIS);
        if (IS_ERR(pb->enable_gpio)) {
                ret = dev_err_probe(&pdev->dev, PTR_ERR(pb-

quoted

enable_gpio),

-                                   "failed to acquire enable
GPIO\n");
+                                   "failed to acquire enable GPIO:
%ld\n",
+                                   PTR_ERR(pb->enable_gpio));

AFAIK dev_err_probe already emits the error code passed as 2nd
parameter. So I wonder about this patch's benefit.

It does. Other messages only take the deferred_probe_reason without the
error code. It's actually fine if users properly enable debugging after
seeing an error and then this change is not needed :)

I'm unsure what you intend to say here. Do you agree that this patch
doesn't need to be applied as it doesn't add any information to the
emitted messages? Or do you think there is a value because "users don't
need to enable debugging" then. In the latter case I don't see where
users would see "failed to acquire enable GPIO" before, but not the
value of the error code.

Best regards
Uwe