On 30/03/2017 22:56, Mason wrote: > I've run into an issue. > > If I boot the system with earlyprintk enabled (as I've > been doing throughout my dev), things work as expected. > > But if I boot with earlyprintk disabled, then the system > does not "see" the PCIe board, because reading the vendor > ID returns 0xffffffff. > > What we think is happening, is that when earlyprintk is > disabled, the system proceeds much faster through the > various inits, and the PCIe init happens when PCIe > link training has not completed yet. > > If that is the case, then it seems I would need to check > the link state in my probe function. I determined empirically that link training takes around 10-15 ms. Though I suppose this might depend on the specific PCIe board? (I'm only considering x1 link.) So I added an msleep(20); in the probe function, and in the config_read callback, I check the link status on the first read to the device. Should I msleep(40) to be safe? Regards.
