On Sun, 5 Feb 2023 at 01:10, Jan Hoffmann <j...@3e8.eu> wrote: > > > Am 02.02.23 um 11:54 schrieb Robert Marko: > > On Tue, 31 Jan 2023 at 23:52, Jan Hoffmann <j...@3e8.eu> wrote: > >> > >> Hi Robert, > >> > >> > >> On 2023-01-30 at 00:08, Robert Marko wrote: > >>> Shouldn't it be possible for the modem driver itself to be fixed > >>> instead of faking > >>> the PCI details? > >> > >> This hack is definitely far from ideal, but I'm not sure if there is a > >> better way to fix this. > >> > >> Here are a few more details about the issue: > >> > >> On the affected devices (so far, three users reported it on the VRX518 > >> thread in the forum [0]), the function call to turn on the "EMA" > >> hardware unit in the vrx518_tc driver [1] fails with the error mentioned > >> in the commit message. > >> > >> I don't have any details about it, but this EMA unit is part of the data > >> path (it is also referenced in the ltq-atm and ltq-ptm data path drivers > >> for older Lantiq modems). If the EMA unit is not running, then at least > >> the transmit data path doesn't work, and any packets the driver writes > >> to the TX ring are not actually sent out by the device. > >> > >> This is also reproducible on non-affected devices by calling tc_clkoff > >> instead of tc_clkon in the vrx518_tc driver (i.e. disabling the hardware > >> unit). The same issue also occurs on affected devices running vendor > >> firmware, if the "magic" in the PCIe driver is disabled in the device > >> tree. So this is not just a bug in the data path driver. > > > > I get the issue, however, I am failing to see how faking the PCI ID for the > > root adaptor is magically solving that? > > If that works, why can't you just patch the driver to stop looking for > > the ancient > > Lantiq ID? > > As far as I can see, the magic values don't appear anywhere in the DSL > drivers. So it doesn't seem like there is an easy fix like that. > > To me this looks like whatever access to these values is being done, > seems to happen in hardware (or firmware). Maybe there are some > revisions or variants of the modem that don't like to cooperate with > non-Lantiq SoCs. > > But in the end, I don't know with certainty what exactly is happening > here, as about the only public information on these modems are the > open-source drivers (including the magic hack in the PCIe driver which > in its original form contains comments like "do some magic" without > really explaining what it actually does).
Ok, I am now getting the issue, it's probably in the damn firmware. I still really dont like the hack that we are gonna need to carry forever. I would like for somebody else to chime in as well. Regards, Robert > > Regards, > Jan > > > > > > Regards, > > Robert > >> > >> > >> Regards, > >> Jan > >> > >> > >>> > >>> Especially considering that now modem support is not self-contained > >>> and will require > >>> patching the DWC Qualcomm PCI driver forever. > >>> > >>> Regards, > >>> Robert > >> > >> > >> [0] > >> https://forum.openwrt.org/t/adding-support-for-vrx518-and-maybe-vrx320/55160 > >> [1] > >> https://gitlab.com/prpl-foundation/intel/vrx518_tc_drv/-/blob/ugw-8.5.2/dcdp/tc_main.c#L112 > > _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/mailman/listinfo/openwrt-devel