malidp_runtime_pm_resume() calls clk_prepare_enable() three times without checking the return value. If any clock fails to enable, the driver silently proceeds with unclocked hardware, leading to undefined behavior.
Convert both the resume and suspend paths to use the clk_bulk API: clk_bulk_prepare_enable() in resume checks the return value and rolls back any successfully enabled clocks on failure; clk_bulk_disable_unprepare() in suspend keeps the two paths symmetric. This issue was found by code review without access to Mali DP hardware. Signed-off-by: Gustavo Kenji Mendonça Kaneko <[email protected]> --- Changes in v2: - Also convert malidp_runtime_pm_suspend() to clk_bulk_disable_unprepare() to make both paths truly symmetric (Liviu Dudau) - Drop the incorrect claim about existing clk_bulk usage in the suspend path from the commit message (Liviu Dudau) drivers/gpu/drm/arm/malidp_drv.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c index b765f6c9eea4..90e7f14aacec 100644 --- a/drivers/gpu/drm/arm/malidp_drv.c +++ b/drivers/gpu/drm/arm/malidp_drv.c @@ -670,6 +670,11 @@ static int malidp_runtime_pm_suspend(struct device *dev) struct drm_device *drm = dev_get_drvdata(dev); struct malidp_drm *malidp = drm_to_malidp(drm); struct malidp_hw_device *hwdev = malidp->dev; + struct clk_bulk_data clks[] = { + { .clk = hwdev->pclk }, + { .clk = hwdev->aclk }, + { .clk = hwdev->mclk }, + }; /* we can only suspend if the hardware is in config mode */ WARN_ON(!hwdev->hw->in_config_mode(hwdev)); @@ -677,9 +682,7 @@ static int malidp_runtime_pm_suspend(struct device *dev) malidp_se_irq_fini(hwdev); malidp_de_irq_fini(hwdev); hwdev->pm_suspended = true; - clk_disable_unprepare(hwdev->mclk); - clk_disable_unprepare(hwdev->aclk); - clk_disable_unprepare(hwdev->pclk); + clk_bulk_disable_unprepare(ARRAY_SIZE(clks), clks); return 0; } @@ -689,10 +692,17 @@ static int malidp_runtime_pm_resume(struct device *dev) struct drm_device *drm = dev_get_drvdata(dev); struct malidp_drm *malidp = drm_to_malidp(drm); struct malidp_hw_device *hwdev = malidp->dev; + struct clk_bulk_data clks[] = { + { .clk = hwdev->pclk }, + { .clk = hwdev->aclk }, + { .clk = hwdev->mclk }, + }; + int err; + + err = clk_bulk_prepare_enable(ARRAY_SIZE(clks), clks); + if (err) + return err; - clk_prepare_enable(hwdev->pclk); - clk_prepare_enable(hwdev->aclk); - clk_prepare_enable(hwdev->mclk); hwdev->pm_suspended = false; malidp_de_irq_hw_init(hwdev); malidp_se_irq_hw_init(hwdev); -- 2.54.0
