Date: Sat, 26 Sep 2020 13:20:49 -0700 From: Mark Millard <marklmi@yahoo.com> To: tech-lists <tech-lists@zyxst.net> Cc: freebsd-arm@freebsd.org Subject: Re: RPi4B u-boot based booting and hw.cpufreq.voltage_core and dev.cpu.0.freq use: able to use 2000 MHz Message-ID: <64B39936-7689-4240-A5F9-4DF5EAE4DE42@yahoo.com> In-Reply-To: <20200926133934.GD54660@bastion.zyxst.net> References: <0578EC2B-D21C-46AA-AD3E-CD13985B18FA@yahoo.com> <20200926133934.GD54660@bastion.zyxst.net>
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On 2020-Sep-26, at 06:39, tech-lists <tech-lists at zyxst.net> wrote: > On Sat, Sep 26, 2020 at 12:37:45AM -0700, Mark Millard via freebsd-arm wrote: >> I got access to a 4 GiByte RPi4B that does not have modernized >> eeprom contents. With it I was able to do a u-boot based boot >> of head -r365932 based on the msdosfs on a older microsd card >> that had materials from 2020-Jul-13 (u-boot.bin) and 14 (RPi4B >> materials). I updated EFI/BOOT/bootaa64.efi . The u-boot.bin >> is from my build of sysutils/u-boot-rpi4/ (no local changes). >> >> In this context . . . >> >> I added over_voltage=6 and arm_freq=2000 to config.txt and it >> ends up looking like: >> >> arm_control=0x200 >> arm_64bit=1 >> dtoverlay=disable-bt >> dtoverlay=mmc >> device_tree_address=0x4000 >> kernel=u-boot.bin >> armstub=armstub8-gic.bin >> over_voltage=6 >> arm_freq=2000 >> >> >> Booting based on that resulted in: >> >> dev.bcm2835_cpufreq.0.freq_settings: 2000/-1 600/-1 >> dev.cpu.0.freq_levels: 2000/-1 600/-1 >> dev.cpu.0.freq: 600 >> >> And: >> >> # sysctl dev.cpu.0.freq=2000 >> dev.cpu.0.freq: 600 -> 2000 >> >> worked. (Without the over_voltage it reports 600 and then >> hangs.) Having /etc/sysctl.conf list dev.cpu.0.freq=2000 >> works. > > Exellent! On the basis of your post I went ahead and removed from config.txt > three lines, then added two and rebooted. > > It's now this: > > arm_control=0x200 > arm_64bit=1 > dtoverlay=disable-bt > dtoverlay=mmc > device_tree_address=0x4000 > kernel=u-boot.bin > armstub=armstub8-gic.bin > over_voltage=6 > arm_freq=2000 > > before, when it didn't work, it had this: > [same as above], apart from > gpu_mem=16 > over_voltage=6 > arm_freq=2100 > > In creating the freebsd instance I followed these instructions for 8GB > https://lists.freebsd.org/pipermail/freebsd-arm/2020-August/022162.html > and applied D26344. /etc/rc.conf has powerd loaded > > I was particularly interested in getting this clocked to a reasonable speed as > it's used to build packages with poudriere based on arm7 and aarch64 for > -current. The cortex-A72 is largely memory subsystem limited on the RPi4B compared to, say, the MACCHIATObin Double Shot running at the same clock rate. So I've recently experimented with changing the sdram_freq_min from the default or 400 to 3200 (to match sdram_freq): # more /microsd_efi/config.txt arm_control=0x200 arm_64bit=1 dtoverlay=disable-bt dtoverlay=mmc device_tree_address=0x4000 kernel=u-boot.bin armstub=armstub8-gic.bin over_voltage=6 arm_freq=2000 sdram_freq_min=3200 A benchmark I use suggests I'll see the fastest RPi4B buildworld buildkernel times that I've seen yet when I get around to trying that. ( My benchmarking and testing is based on powerd or the like not being in use but the kernel or rpi-firmware could be doing its own thing given the above and sysctl.conf having dev.cpu.0.freq=2000 .) I have heatsinks and a fan involved, as well as a (apparently good) 5.1v 3.5A power supply. My experiments presume such a context. (I've sent out a separate list message about hw.cpufreq.sdram_freq having a value-display problem and the 3 hw.cpufreq.voltage_sdram_* values looking to be lower than expected. I've not seen evidence of problems in operation so far.) I'll note that: https://www.raspberrypi.org/documentation/configuration/config-txt/boot.md reports: QUOTE arm_control DEPRECATED - use arm_64bit to enable 64-bit kernels. Sets board-specific control bits. END QUOTE So I'm likely to experiment with removing that line from config.txt . > seems very stable so far: > > 2:36p.m. up 45 mins, 1 user, load averages: 6.51, 3.57, 2.92 > Sat 26 Sep 2020 14:36:14 BST > dev.cpu.0.temperature: 65.0C > dev.cpu.0.freq_levels: 2000/-1 600/-1 > dev.cpu.0.freq: 2000 > > rpi4 is in a FLIRC case for cooling, no fan. 24 degC/44%rh ambient. > === Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)help
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