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

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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>
This commit is contained in:
Gustavo Kenji Mendonça Kaneko 2026-06-09 13:08:33 +00:00 committed by Liviu Dudau
parent 46f715a169
commit 6502eb8cfc
2 changed files with 14 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/gpu/drm/arm/display/komeda/komeda_dev.c
View File

@ -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);

14
drivers/gpu/drm/arm/display/komeda/komeda_drv.c
View File

@ -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 @@ static int komeda_platform_probe(struct platform_device *pdev)
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 = {