Re: [PATCH v2] PCI: imx6: Allow to probe when dw_pcie_wait_for_link() fails

[Rob Herring <robh@kernel.org>]

On Thu, Jan 6, 2022 at 4:36 AM Fabio Estevam <festevam@gmail.com> wrote:
>
> The intention of commit 886a9c134755 ("PCI: dwc: Move link handling into
> common code") was to standardize the behavior of link down as explained
> in its commit log:
>
> "The behavior for a link down was inconsistent as some drivers would fail
> probe in that case while others succeed. Let's standardize this to
> succeed as there are usecases where devices (and the link) appear later
> even without hotplug. For example, a reconfigured FPGA device."
>
> The pci-imx6 still fails to probe when the link is not present, which
> causes the following warning:
>
> imx6q-pcie 8ffc000.pcie: Phy link never came up
> imx6q-pcie: probe of 8ffc000.pcie failed with error -110
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 30 at drivers/regulator/core.c:2257 _regulator_put.part.0+0x1b8/0x1dc
> Modules linked in:
> CPU: 0 PID: 30 Comm: kworker/u2:2 Not tainted 5.15.0-next-20211103 #1
> Hardware name: Freescale i.MX6 SoloX (Device Tree)
> Workqueue: events_unbound async_run_entry_fn
> [<c0111730>] (unwind_backtrace) from [<c010bb74>] (show_stack+0x10/0x14)
> [<c010bb74>] (show_stack) from [<c0f90290>] (dump_stack_lvl+0x58/0x70)
> [<c0f90290>] (dump_stack_lvl) from [<c012631c>] (__warn+0xd4/0x154)
> [<c012631c>] (__warn) from [<c0f87b00>] (warn_slowpath_fmt+0x74/0xa8)
> [<c0f87b00>] (warn_slowpath_fmt) from [<c076b4bc>] (_regulator_put.part.0+0x1b8/0x1dc)
> [<c076b4bc>] (_regulator_put.part.0) from [<c076b574>] (regulator_put+0x2c/0x3c)
> [<c076b574>] (regulator_put) from [<c08c3740>] (release_nodes+0x50/0x178)
>
> Fix this problem by ignoring the dw_pcie_wait_for_link() error like
> it is done on the other dwc drivers.
>
> Tested on imx6sx-sdb and imx6q-sabresd boards.
>
> Cc: <stable@vger.kernel.org>
> Fixes: 886a9c134755 ("PCI: dwc: Move link handling into common code")
> Signed-off-by: Fabio Estevam <festevam@gmail.com>
> ---
> Changes since v1:
> - Remove the printk timestamp from the kernel warning log (Richard).
>
>  drivers/pci/controller/dwc/pci-imx6.c | 10 ++--------
>  1 file changed, 2 insertions(+), 8 deletions(-)

Reviewed-by: Rob Herring <robh@kernel.org>