Vélhetően javítva lesz az Intel processzoroknál és bizonyos kernel verzióknál jelentkező hiba, de a javításig is érdemes lépni.
Hiba (dmesg kimenet):
[drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* uncleared fifo underrun on pipe A [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun [drm:intel_set_pch_fifo_underrun_reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcoder A [drm:cpt_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun [Console: switching to colour frame buffer device 170x48 i915 0000:00:02.0: fb0: i915drmfb frame buffer device
GRUB beállítás szerkesztése
A javításra használt kernel paraméter (nem parancssor):
intel_iommu=igfx_off
A kernel paraméterek beállításáról itt olvashatsz:
https://linuxmint.hu/blog/2018/03/kernel-kapcsolok-alkalmazasa-a-grub-fajl-szerkesztesevel
Ezeknél a kernel verzióknál jelentkezik a bug (a GRUB frissítéssel mutatom):
sudo update-grub GRUB beállítófájl előállítása… Found background image: /usr/share/images/desktop-base/desktop-grub.png Megtalált linux lemezkép: /boot/vmlinuz-5.6.0-0.bpo.2-amd64 Megtalált initrd lemezkép: /boot/initrd.img-5.6.0-0.bpo.2-amd64 Megtalált linux lemezkép: /boot/vmlinuz-5.4.0-0.bpo.4-amd64 Megtalált initrd lemezkép: /boot/initrd.img-5.4.0-0.bpo.4-amd64 Megtalált linux lemezkép: /boot/vmlinuz-4.19.0-9-amd64 Megtalált initrd lemezkép: /boot/initrd.img-4.19.0-9-amd64 kész
A javítás után (a hibák nem mutatkoznak):
sudo dmesg | grep drm [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [drm] Driver supports precise vblank timestamp query. [drm] Initialized i915 1.6.0 20200114 for 0000:00:02.0 on minor 0 fbcon: i915drmfb (fb0) is primary device i915 0000:00:02.0: fb0: i915drmfb frame buffer device
... a fenti parancssor az általános vizsgálatra is kiválóan alkalmas.
Ha Intel CPU van a számítógépedben, teszteld!
A CPU hómérséklet alapértékek nem mentek lejjebb:
sensors acpitz-acpi-0 Adapter: ACPI interface temp1: +60.0°C (crit = +128.0°C) temp2: +0.0°C (crit = +128.0°C) temp3: +47.0°C (crit = +128.0°C) temp4: +44.0°C (crit = +128.0°C) temp5: +20.0°C (crit = +128.0°C) temp6: +127.0°C (crit = +128.0°C) coretemp-isa-0000 Adapter: ISA adapter Package id 0: +61.0°C (high = +87.0°C, crit = +105.0°C) Core 0: +60.0°C (high = +87.0°C, crit = +105.0°C) Core 1: +55.0°C (high = +87.0°C, crit = +105.0°C)
... azonban remélhető, hogy nem fut fel 100 °C fölé, mint korábban.
A teszt rendszer: Debian 10 Buster
Enjoy :-)
Intel IOMMU és hasonló kernel paraméterek:
intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option on Enable intel iommu driver. off Disable intel iommu driver. igfx_off [Default Off] By default, gfx is mapped as normal device. If a gfx device has a dedicated DMAR unit, the DMAR unit is bypassed by not enabling DMAR with this option. In this case, gfx device will use physical address for DMA. forcedac [x86_64] With this option iommu will not optimize to look for io virtual address below 32-bit forcing dual address cycle on pci bus for cards supporting greater than 32-bit addressing. The default is to look for translation below 32-bit and if not available then look in the higher range. strict [Default Off] With this option on every unmap_single operation will result in a hardware IOTLB flush operation as opposed to batching them for performance. sp_off [Default Off] By default, super page will be supported if Intel IOMMU has the capability. With this option, super page will not be supported. ecs_off [Default Off] By default, extended context tables will be supported if the hardware advertises that it has support both for the extended tables themselves, and also PASID support. With this option set, extended tables will not be used even on hardware which claims to support them. tboot_noforce [Default Off] Do not force the Intel IOMMU enabled under tboot. By default, tboot will force Intel IOMMU on, which could harm performance of some high-throughput devices like 40GBit network cards, even if identity mapping is enabled. Note that using this option lowers the security provided by tboot because it makes the system vulnerable to DMA attacks. intel_idle.max_cstate= [KNL,HW,ACPI,X86] 0 disables intel_idle and fall back on acpi_idle. 1 to 9 specify maximum depth of C-state. intel_pstate= [X86] disable Do not enable intel_pstate as the default scaling driver for the supported processors passive Use intel_pstate as a scaling driver, but configure it to work with generic cpufreq governors (instead of enabling its internal governor). This mode cannot be used along with the hardware-managed P-states (HWP) feature. force Enable intel_pstate on systems that prohibit it by default in favor of acpi-cpufreq. Forcing the intel_pstate driver instead of acpi-cpufreq may disable platform features, such as thermal controls and power capping, that rely on ACPI P-States information being indicated to OSPM and therefore should be used with caution. This option does not work with processors that aren't supported by the intel_pstate driver or on platforms that use pcc-cpufreq instead of acpi-cpufreq. no_hwp Do not enable hardware P state control (HWP) if available. hwp_only Only load intel_pstate on systems which support hardware P state control (HWP) if available. support_acpi_ppc Enforce ACPI _PPC performance limits. If the Fixed ACPI Description Table, specifies preferred power management profile as "Enterprise Server" or "Performance Server", then this feature is turned on by default. per_cpu_perf_limits Allow per-logical-CPU P-State performance control limits using cpufreq sysfs interface
A 4.14-es kernelben alapértelmezett az intel_iommu=igfx_off beálítás, az általam használt kernelekben azonban nem.
Forrás: https://www.kernel.org/doc/html/v4.14/admin-guide/kernel-parameters.html
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Keresés az ERROR kifejezésre az összes rendszer naplóban (terminálban):
sudo grep -insr "ERROR" /var/log
Ugyanezzel a módszerrel rákereshetsz a WARNING, a failed, a drm vagy más kifejezésre.
A grep kézikönyve (a paraméterek magyarázataival -> -insr):
man grep