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SubjectRe: [PATCH v1] driver core: Fix handling of fw_devlink=permissive
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Hi,

On 2020-03-31 04:28, Saravana Kannan wrote:
> When commit 8375e74f2bca ("driver core: Add fw_devlink kernel
> commandline option") added fw_devlink, it didn't implement "permissive"
> mode correctly.
>
> That commit got the device links flags correct to make sure unprobed
> suppliers don't block the probing of a consumer. However, if a consumer
> is waiting for mandatory suppliers to register, that could still block a
> consumer from probing.
>
> This commit fixes that by making sure in permissive mode, all suppliers
> to a consumer are treated as a optional suppliers. So, even if a
> consumer is waiting for suppliers to register and link itself (using the
> DL_FLAG_SYNC_STATE_ONLY flag) to the supplier, the consumer is never
> blocked from probing.
>
> Fixes: 8375e74f2bca ("driver core: Add fw_devlink kernel commandline option")
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Saravana Kannan <saravanak@google.com>
> ---
> Hi Marek,
>
> If you pull in this patch and then add back in my patch that created the
> boot problem for you, can you see if that fixes the boot issue for you?

Indeed, this fixes booting on my Raspberry Pi3/4 boards with linux
next-20200327. Thanks! :)

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>

>
> Thanks,
> Saravana
>
> drivers/base/core.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 5e3cc1651c78..1be26a7f0866 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -2370,6 +2370,11 @@ u32 fw_devlink_get_flags(void)
> return fw_devlink_flags;
> }
>
> +static bool fw_devlink_is_permissive(void)
> +{
> + return fw_devlink_flags == DL_FLAG_SYNC_STATE_ONLY;
> +}
> +
> /**
> * device_add - add device to device hierarchy.
> * @dev: device.
> @@ -2524,7 +2529,7 @@ int device_add(struct device *dev)
> if (fw_devlink_flags && is_fwnode_dev &&
> fwnode_has_op(dev->fwnode, add_links)) {
> fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
> - if (fw_ret == -ENODEV)
> + if (fw_ret == -ENODEV && !fw_devlink_is_permissive())
> device_link_wait_for_mandatory_supplier(dev);
> else if (fw_ret)
> device_link_wait_for_optional_supplier(dev);

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland

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