> -----Original Message----- > From: Rob Herring <robh@xxxxxxxxxx> > Sent: 2022年4月2日 4:27 > To: Hongxing Zhu <hongxing.zhu@xxxxxxx> > Cc: l.stach@xxxxxxxxxxxxxx; bhelgaas@xxxxxxxxxx; broonie@xxxxxxxxxx; > lorenzo.pieralisi@xxxxxxx; jingoohan1@xxxxxxxxx; festevam@xxxxxxxxx; > francesco.dolcini@xxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > kernel@xxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx> > Subject: Re: [PATCH v8 8/8] PCI: imx6: Add compliance tests mode support > > On Fri, Feb 25, 2022 at 11:44:27AM +0800, Richard Zhu wrote: > > Refer to the Chapter 3.2 System Board Signal Quality of PCI Express > > Architecture PHY Test Specification Revision 2.0. > > > > Signal quality tests (for example: jitter, differential eye opening > > and so on) can be executed with devices in the polling.compliance state. > > > > To let the device support polling.compliance state, the clocks and > > powers shouldn't be turned off when the probe of device driver fails. > > > > Based on CLB (Compliance Load Board) Test Fixture and so on test > > equipments, the PHY link would be down during the compliance tests. > > Refer to this scenario, add the i.MX PCIe compliance tests mode enable > > support, and keep the clocks and powers on, and finish the driver > > probe without error return. > > How is this specific to i.MX? If there's a need for compliance test mode, then > shouldn't it be common? However, while your usecase is compliance testing, > there doesn't seem to be any need for the kernel to know what the usecase is. > > In the same series you've argued both ways. You need the driver to probe > successfully with no link and you need it to shutdown on no link. > Hi Rob: Thank a lot for your review comments. Based on this series, to save power consumption, i.MX PCIe would turn off the power/clocks when probe failed. Thus, it's specific to i.MX to add one more option to keep power/clocks on when compliance tests mode is required. The compliance test mode can be enabled dynamically through the module_para setting. Best Regards Richard Zhu > > > > Use the "pci_imx6.compliance=1" in kernel command line to enable the > > compliance tests mode. > > > > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx> > > --- > > drivers/pci/controller/dwc/pci-imx6.c | 47 > > ++++++++++++++++++--------- > > 1 file changed, 31 insertions(+), 16 deletions(-)
