Date: Fri, 16 Nov 2018 08:35:29 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Rajesh Kumar <rajfbsd@gmail.com> Cc: freebsd-amd64@freebsd.org, freebsd-acpi@freebsd.org, freebsd-hackers@freebsd.org Subject: Re: Enabling a ACPI eMMC device is causing kernel reboots with FreeBSD 11.2 Message-ID: <20181116063529.GP2378@kib.kiev.ua> In-Reply-To: <CAAO%2BANPLyU7739hOYecbct_6X9P1OwyPPXPQOp9QKBMytS0H=g@mail.gmail.com> References: <CAAO%2BANPD-K92dwUpQKWA%2BxTChbdxW8stXc=6mOq36zsGRk_5DA@mail.gmail.com> <CAAO%2BANPLyU7739hOYecbct_6X9P1OwyPPXPQOp9QKBMytS0H=g@mail.gmail.com>
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On Fri, Nov 16, 2018 at 10:45:39AM +0530, Rajesh Kumar wrote: > Hi, > > I did some study on this. During acpi_attach, if MCFG table is present, > FreeBSD tries to use it (That is to map the PCI Base address to virtual > address space). Setting hw.pci.mcfg=0, disables that mapping and lets the > system use the type 1 config access (which is IO port based access). So, > this is what hw.pci.mcfg does. > > In our case, we are enabling a device on the ACPI bus and made sure no > other ACPI device collides with the address range for PCI (which mcfg > says). So, why enabling a device on ACPI, is causing the memory mapped PCI > access go bad to panic/reboot the kernel? I tried to collect more info > enabling INVARIANTS, but in that case kernel panics much before in the boot > process. So, how could I proceed in debugging this issue? Any suggestions? There is no ACPI bus, at best the device is enumerated using ACPI. > > > On Thu, Nov 8, 2018 at 4:14 PM Rajesh Kumar <rajfbsd@gmail.com> wrote: > > > Hi, > > > > I have amd64 board, which has a eMMC device on the ACPI bus. When I try > > booting FreeBSD 11.2 on this board, with eMMC device disabled in BIOS, it > > boots without any issues. But, when eMMC device is enabled in BIOS, > > FreeBSD 11.2 continuously reboots. What is the CPU in your motherboard ? If it is AMD, try HEAD or latest 12.0 BETA. > > > > When I have the following tunable set, FreeBSD 11.2 boots without any > > issues with eMMC enabled. > > hw.pci.mcfg=0 > > > > Observations : > > a) We have verified the ACPI device addresses (from DSDT table) doesn't > > conflict with the PCI address base (configured in MCFG table). > > b) The PCI address base from MCFG table is read correctly by kernel > > (Verbose boot prints that address). So, I don't think MCFG table pointer is > > corrupted and getting read properly. > > > > Questions : > > a) What does hw.pci.mcfg=0 actually do to get the reboot issue resolved? > > b) Why enabling a device on ACPI bus needs hw.pci.mcfg (PCI specific) to > > boot? > > > > Looks like the system reboots when the ACPI and PCI devices enumeration > > starts during the boot. So, seems ACPI (or) PCI devices aren't getting > > enough resources and so reboots. > > > > Thanks, > > Rajesh. > > > _______________________________________________ > freebsd-amd64@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-amd64 > To unsubscribe, send any mail to "freebsd-amd64-unsubscribe@freebsd.org"
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