From: Gustavo Kenji Mendonça Kaneko <kaneko.dev@pm.me>
Date: Tue, 9 Jun 2026 13:08:33 +0000 (+0000)
Subject: drm/arm/komeda: fix error handling for clk_prepare_enable() and callers
X-Git-Tag: v7.2-rc2~10^2^2~15
X-Git-Url: http://git.ipfire.org/index.cgi?a=commitdiff_plain;h=6502eb8cfcd6f7bc5f1f8b73ee524112bd93319d;p=thirdparty%2Flinux.git

drm/arm/komeda: fix error handling for clk_prepare_enable() and callers

komeda_dev_resume() calls clk_prepare_enable() without checking the
return value. If the clock fails to enable, the function returns 0
(success) while IRQs are enabled and IOMMU is connected on potentially
unclocked hardware, causing undefined behavior on resume.

Propagate the error from clk_prepare_enable() and fix all call sites
in komeda_drv.c that previously ignored the return value of
komeda_dev_resume():

- komeda_platform_probe(): if resume fails, jump to err_destroy_mdev
  (skipping the suspend call, since the clock was never enabled)
- komeda_pm_resume(): propagate the error and skip
  drm_mode_config_helper_resume() on failure

This issue was found by code review without access to Komeda hardware.

Signed-off-by: Gustavo Kenji Mendonça Kaneko <kaneko.dev@pm.me>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patch.msgid.link/20260609130828.1066038-1-kaneko.dev@pm.me
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
---

diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_dev.c b/drivers/gpu/drm/arm/display/komeda/komeda_dev.c
index 5ba62e637a616..9aad1d1d28ec0 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_dev.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_dev.c
@@ -313,7 +313,11 @@ void komeda_dev_destroy(struct komeda_dev *mdev)
 
 int komeda_dev_resume(struct komeda_dev *mdev)
 {
-	clk_prepare_enable(mdev->aclk);
+	int err;
+
+	err = clk_prepare_enable(mdev->aclk);
+	if (err)
+		return err;
 
 	mdev->funcs->enable_irq(mdev);
 
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_drv.c b/drivers/gpu/drm/arm/display/komeda/komeda_drv.c
index 4bb5f250e95ef..67fffab018ae8 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_drv.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_drv.c
@@ -74,8 +74,11 @@ static int komeda_platform_probe(struct platform_device *pdev)
 	}
 
 	pm_runtime_enable(dev);
-	if (!pm_runtime_enabled(dev))
-		komeda_dev_resume(mdrv->mdev);
+	if (!pm_runtime_enabled(dev)) {
+		err = komeda_dev_resume(mdrv->mdev);
+		if (err)
+			goto err_destroy_mdev;
+	}
 
 	mdrv->kms = komeda_kms_attach(mdrv->mdev);
 	if (IS_ERR(mdrv->kms)) {
@@ -93,7 +96,7 @@ destroy_mdev:
 		pm_runtime_disable(dev);
 	else
 		komeda_dev_suspend(mdrv->mdev);
-
+err_destroy_mdev:
 	komeda_dev_destroy(mdrv->mdev);
 
 free_mdrv:
@@ -140,11 +143,12 @@ static int __maybe_unused komeda_pm_suspend(struct device *dev)
 static int __maybe_unused komeda_pm_resume(struct device *dev)
 {
 	struct komeda_drv *mdrv = dev_get_drvdata(dev);
+	int err = 0;
 
 	if (!pm_runtime_status_suspended(dev))
-		komeda_dev_resume(mdrv->mdev);
+		err = komeda_dev_resume(mdrv->mdev);
 
-	return drm_mode_config_helper_resume(&mdrv->kms->base);
+	return err ? err : drm_mode_config_helper_resume(&mdrv->kms->base);
 }
 
 static const struct dev_pm_ops komeda_pm_ops = {