On Tue, Jun 06, 2023 at 04:36:06PM +0100, Jon Hunter wrote:
> From: Bharat Nihalani <bnihalani@xxxxxxxxxx>
>
> The kernel command line parameter debugfs=off can be used to dynamically
> disable debugfs support at boot time. However, the Tegra PMC driver will
> always attempt to register debugfs entries if CONFIG_DEBUG_FS is
> enabled. Therefore, if CONFIG_DEBUG_FS is enabled but the user sets
> debugfs=off, then probing the PMC driver will fail.
>
> Fix this by using the function debugfs_initialized() to check if debugfs
> support is enabled before calling any debugfs functions in the Tegra PMC
> driver. Note that if CONFIG_DEBUG_FS is not defined
> debugfs_initialized() will return false.
>
> Signed-off-by: Bharat Nihalani <bnihalani@xxxxxxxxxx>
> Signed-off-by: Kartik <kkartik@xxxxxxxxxx>
> Co-developed-by: Jon Hunter <jonathanh@xxxxxxxxxx>
> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
> ---
> drivers/soc/tegra/pmc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
> index 5d17799524c9..12e852a8a609 100644
> --- a/drivers/soc/tegra/pmc.c
> +++ b/drivers/soc/tegra/pmc.c
> @@ -3026,7 +3026,7 @@ static int tegra_pmc_probe(struct platform_device *pdev)
>
> tegra_pmc_reset_sysfs_init(pmc);
>
> - if (IS_ENABLED(CONFIG_DEBUG_FS)) {
> + if (debugfs_initialized()) {
> err = tegra_powergate_debugfs_init();
> if (err < 0)
> goto cleanup_sysfs;
Judging by other patches I've seen sent over the last few years, I think
the more idiomatic fix would be to just ignore the error returns from
debugfs calls. I think in this particular case we can probably just make
tegra_powergate_debugfs_init() return void. Any subsequent calls using
the pmc->debugfs pointer will ignore errors or NULL.
Can you test whether something like the below fixes the problem you were
seeing as well?
--- >8 ---
diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
index 5d17799524c9..16992ddd6e04 100644
--- a/drivers/soc/tegra/pmc.c
+++ b/drivers/soc/tegra/pmc.c
@@ -1190,14 +1190,10 @@ static int powergate_show(struct seq_file *s, void *data)
DEFINE_SHOW_ATTRIBUTE(powergate);
-static int tegra_powergate_debugfs_init(void)
+static void tegra_powergate_debugfs_init(void)
{
pmc->debugfs = debugfs_create_file("powergate", S_IRUGO, NULL, NULL,
&powergate_fops);
- if (!pmc->debugfs)
- return -ENOMEM;
-
- return 0;
}
static int tegra_powergate_of_get_clks(struct tegra_powergate *pg,
@@ -3026,11 +3022,8 @@ static int tegra_pmc_probe(struct platform_device *pdev)
tegra_pmc_reset_sysfs_init(pmc);
- if (IS_ENABLED(CONFIG_DEBUG_FS)) {
- err = tegra_powergate_debugfs_init();
- if (err < 0)
- goto cleanup_sysfs;
- }
+ if (IS_ENABLED(CONFIG_DEBUG_FS))
+ tegra_powergate_debugfs_init();
err = tegra_pmc_pinctrl_init(pmc);
if (err)
@@ -3067,7 +3060,6 @@ static int tegra_pmc_probe(struct platform_device *pdev)
tegra_powergate_remove_all(pdev->dev.of_node);
cleanup_debugfs:
debugfs_remove(pmc->debugfs);
-cleanup_sysfs:
device_remove_file(&pdev->dev, &dev_attr_reset_reason);
device_remove_file(&pdev->dev, &dev_attr_reset_level);
clk_notifier_unregister(pmc->clk, &pmc->clk_nb);
--- >8 ---
Thanks,
Thierry
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