linux-kernel - [PATCH] Revert "backlight: pwm: Handle EPROBE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 26 Sep 2015 21:24:42 +0200
From:	Robert Jarzmik <robert.jarzmik@...e.fr>
To:	Thierry Reding <thierry.reding@...il.com>,
	Jingoo Han <jingoohan1@...il.com>,
	Lee Jones <lee.jones@...aro.org>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Tomi Valkeinen <tomi.valkeinen@...com>
Cc:	linux-pwm@...r.kernel.org, linux-fbdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Robert Jarzmik <robert.jarzmik@...e.fr>
Subject: [PATCH] Revert "backlight: pwm: Handle EPROBE_DEFER while requesting the PWM"

This reverts commit 68feaca0b13e453aa14ee064c1736202b48b342f.
This commit breaks legacy platforms, for which :
 (a) no pwm table is added (legacy platforms)
 (b) in this case, in pwm_get(), pmw_lookup_list is empty, and therefore
     chosen == NULL, and therefore pwm_get() returns NULL, and pwm_get()
     returns -EPROBE_DEFER
 (c) as a consequence, this code is unreachable in pwm_bl.c :
     if (IS_ERR(pb->pwm)) {
	ret = PTR_ERR(pb->pwm);
 	dev_info(&pdev->dev, "%s:%d(): %d\n", __func__, __LINE__, ret);
 	if (ret == -EPROBE_DEFER)
 		goto err_alloc;

 	dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
 	pb->legacy = true;
 	pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");

As this code is unreachable, all legacy platforms relying on pwm_id are
broken, amongst which pxa have been tested as broken.

Signed-off-by: Robert Jarzmik <robert.jarzmik@...e.fr>
---
 drivers/video/backlight/pwm_bl.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index eff379b234cc..57cb9ec8be43 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -272,10 +272,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 
 	pb->pwm = devm_pwm_get(&pdev->dev, NULL);
 	if (IS_ERR(pb->pwm)) {
-		ret = PTR_ERR(pb->pwm);
-		if (ret == -EPROBE_DEFER)
-			goto err_alloc;
-
 		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
 		pb->legacy = true;
 		pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
-- 
2.1.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/