On Thu, Jul 28, 2022 at 03:16:08PM +0200, Lukasz Bartosik wrote:
> From: Łukasz Bartosik <lb@xxxxxxxxxxxx>
>
> A thunderbolt
> lspci -d 8086:9a1b -vmmknn
> Slot: 00:0d.2
> Class: System peripheral [0880]
> Vendor: Intel Corporation [8086]
> Device: Tiger Lake-LP Thunderbolt 4 NHI #0 [9a1b]
>
> presents itself with PCI class 0x088000 after Chromebook boots.
> lspci -s 00:0d.2 -xxx
> 00:0d.2 System peripheral: Intel Corporation Tiger Lake-LP Thunderbolt 4
> NHI #0 (rev 01)
> 00: 86 80 1b 9a 00 00 10 00 01 00 80 08 00 00 00 00
> ...
>
> However after thunderbolt is powered up in nhi_probe()
> its class changes to 0x0c0340
> lspci -s 00:0d.2 -xxx
> 00:0d.2 System peripheral: Intel Corporation Tiger Lake-LP Thunderbolt 4
> NHI #0 (rev 01)
> 00: 86 80 1b 9a 06 04 10 00 01 40 03 0c 00 00 00 00
> ...
>
> which leaves pci_dev structure with old class value
> cat /sys/bus/pci/devices/0000:00:0d.2/class
> 0x088000
>
> This fix updates PCI device class in pci_dev structure after
> thunderbolt is powered up.
>
> Fixes: 3cdb9446a117 ("thunderbolt: Add support for Intel Ice Lake")
> Signed-off-by: Łukasz Bartosik <lb@xxxxxxxxxxxx>
> ---
> drivers/thunderbolt/nhi_ops.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/thunderbolt/nhi_ops.c b/drivers/thunderbolt/nhi_ops.c
> index 96da07e88c52..6a343d7e3f90 100644
> --- a/drivers/thunderbolt/nhi_ops.c
> +++ b/drivers/thunderbolt/nhi_ops.c
> @@ -160,12 +160,17 @@ static int icl_nhi_suspend_noirq(struct tb_nhi *nhi, bool wakeup)
>
> static int icl_nhi_resume(struct tb_nhi *nhi)
> {
> + u32 class;
> int ret;
>
> ret = icl_nhi_force_power(nhi, true);
> if (ret)
> return ret;
>
> + /* Set device class code as it might have changed after powering up */
> + pci_read_config_dword(nhi->pdev, PCI_CLASS_REVISION, &class);
> + nhi->pdev->class = class >> 8;
What about the revision field, why not set that as well:
nhi->pdev->revision = class & 0xff;
If the value is overwritten for 3 of the bytes, why not the 4th?
Also this feels odd, what is changing the bytes here? Why only the
class? What else changed and what caused it?
thanks,
greg k-h
