Re: [PATCH v4] PCI: imx6: Add suspend/resume support for i.MX6QDL

["Krzysztof Wilczyński" <kw@linux.com>]

Hello,

> The suspend/resume functionality is currently broken on the i.MX6QDL
> platform, as documented in the NXP errata (ERR005723):
> https://www.nxp.com/docs/en/errata/IMX6DQCE.pdf
> 
> This patch addresses the issue by sharing most of the suspend/resume
> sequences used by other i.MX devices, while avoiding modifications to
> critical registers that disrupt the PCIe functionality. It targets the
> same problem as the following downstream commit:
> https://github.com/nxp-imx/linux-imx/commit/4e92355e1f79d225ea842511fcfd42b343b32995
> 
> Unlike the downstream commit, this patch also resets the connected PCIe
> device if possible. Without this reset, certain drivers, such as ath10k
> or iwlwifi, will crash on resume. The device reset is also done by the
> driver on other i.MX platforms, making this patch consistent with
> existing practices.
> 
> Without this patch, suspend/resume will fail on i.MX6QDL devices if a
> PCIe device is connected. Upon resuming, the kernel will hang and
> display an error. Here's an example of the error encountered with the
> ath10k driver:
> ath10k_pci 0000:01:00.0: Unable to change power state from D3hot to D0, device inaccessible
> Unhandled fault: imprecise external abort (0x1406) at 0x0106f944

Applied to controller/imx6, thank you!

[01/01] PCI: imx6: Fix suspend/resume support on i.MX6QDL
        https://git.kernel.org/pci/pci/c/1a2a9024f84d

	Krzysztof