Hi, On Mon, 2021-10-18 at 14:46 +0200, Loic Poulain wrote: > On Mon, 18 Oct 2021 at 13:26, Thomas Perrot < > thomas.perrot@xxxxxxxxxxx> wrote: > > > > Hi Loic, > > > > On Mon, 2021-10-18 at 11:59 +0200, Loic Poulain wrote: > > > Hi Aleksander, > > > > > > On Mon, 18 Oct 2021 at 11:14, Aleksander Morgado > > > <aleksander@xxxxxxxxxxxxx> wrote: > > > > > > > > Hey all, > > > > > > > > > [ 7.056113] mhi-pci-generic 0000:01:00.0: MHI PCI device > > > > > found: > > > > > sierra-em919x > > > > > [ 7.063298] mhi-pci-generic 0000:01:00.0: BAR 0: assigned > > > > > [mem > > > > > 0x600000000-0x600000fff 64bit] > > > > > [ 7.071846] mhi-pci-generic 0000:01:00.0: enabling device > > > > > (0000 > > > > > -> 0002) > > > > > [ 7.078671] mhi-pci-generic 0000:01:00.0: using shared MSI > > > > > > > > In this specific setup we request 4 MSI vectors through > > > > pci_alloc_irq_vectors(), but only end up allocating a single > > > > one > > > > (i.e. > > > > mhi_cntrl->nr_irqs = 1). Could that be related to the problem > > > > somehow? > > > > > > It shouldn't, we have the 'shared IRQ' fallback which is used > > > when we > > > can not setup multiple MSI, and this works with other SDX55 based > > > modems. > > > > > > > Compared to other SDX55 based modems, EM919x uses the same event > > ring > > for the control, the data and the diag, and we use the macro > > MHI_EVENT_CONFIG_CTRL to configure it. > > - Perhaps this macro is not suitable in this case? > > Well it should work, but it's usually better to have a dedicated > event > ring for non-control stuff. > The number of event ring is normally driven by the host, is it a > limitation with EM919X? I asked the question to our Sierra distributor, because it isn't indicated in the technical documentation that I have, I'm still waiting for the answer. > What is done in the downstream driver? As we encountered issues with the generic event ring configuration, I tried with a configuration equivalent to that of the vendor driver, that uses the same ring for data, control and diag stuff. Best regards, Thomas > > > - Could this be explaining, what are we observing? > > Hmm, as I said device should follow what the host is configuring in > terms of event rings, but maybe in your case a specific configuration > is expected, so it would be nice to double check with what is done in > the downstream driver. As well, do you have any way to access the > serial/debug console of the EM919X? > > > Moreover, we have voluntarily reduced the number of shared MSI > > vectors > > to one, on a platform able to provide enough, then we observe the > > same > > kind of issues, as on i.MX6DL which end up allocating a single one. > > However, we carried out this test only with the vendor driver. > > You mean the same initialization issue? > > Regards, > Loic -- Thomas Perrot, Bootlin Embedded Linux and kernel engineering https://bootlin.com
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