Linux下检查显存大小

使用 lspci 检查显存大小

首先使用 lspci 命令列出所有 PCI 设备：

[root@localhost ~]# lspci

00:00.0 Host bridge: Intel Corporation 82845G/GL[Brookdale-G]/GE/PE DRAM Controller/Host-Hub Interface (rev 03)

00:02.0 VGA compatible controller: Intel Corporation 82845G/GL[Brookdale-G]/GE Chipset Integrated Graphics Device (rev 03)

00:1d.0 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #1 (rev 02)

00:1d.1 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #2 (rev 02)

00:1d.2 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #3 (rev 02)

00:1d.7 USB Controller: Intel Corporation 82801DB/DBM (ICH4/ICH4-M) USB2 EHCI Controller (rev 02)

00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 82)

00:1f.0 ISA bridge: Intel Corporation 82801DB/DBL (ICH4/ICH4-L) LPC Interface Bridge (rev 02)

00:1f.1 IDE interface: Intel Corporation 82801DB (ICH4) IDE Controller (rev 02)

00:1f.3 SMBus: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) SMBus Controller (rev 02)

00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 02)

01:00.0 Network controller: RaLink RT2561/RT61 rev B 802.11g

01:02.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture (rev 11)

01:02.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture (rev 11)

01:05.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)

从上面的输出可以看到 00:02.0 为 VGA 显卡设备，继续使用 lspci 命令查看显存大小:

[root@localhost ~]# lspci -v -s 00:02.0

00:02.0 VGA compatible controller: Intel Corporation 82845G/GL[Brookdale-G]/GE Chipset Integrated Graphics Device (rev 03) (prog-if 00 [VGA])

Subsystem: Giga-byte Technology Unknown device 2562

Flags: bus master, fast devsel, latency 0, IRQ 177

Memory at d0000000 (32-bit, prefetchable) [size=128M]

Memory at d8200000 (32-bit, non-prefetchable) [size=512K]

可以看到显存大小为 128 MB。

通过 Xorg 日志检查显存大小

Xorg 运行日志中一般都会显示显卡及显存信息：

[root@localhost ~]# grep -i --color memory /var/log/Xorg.0.log

(--) Aug 02 12:16:20 NVIDIA(0): Memory: 1048576 kBytes

(II) Aug 02 12:16:21 NVIDIA: Using 768.00 MB of virtual memory for indirect memory access.

(==) NVIDIA(0): Disabling shared memory pixmaps

上面的日志输出显示系统中的 Nvidia 显卡拥有 1024 MB 显存。

如果是共享主内存的集成显卡，例如 Macbook 上使用的 Intel GM965 显卡也可以从日志中看到：

[root@localhost ~]# grep -i memory /var/log/Xorg.0.log

[2318869.434] (II) intel(0): detected 15868 kB stolen memory.

[2318869.472] (II) intel(0): I830CheckAvailableMemory: 1966080 kB available

[2318869.486] (II) intel(0): Attempting memory allocation with tiled buffers.

[2318870.197] (II) intel(0): Fixed memory allocation layout:

[2318870.197] (II) intel(0): 0x00f7f000: end of stolen memory

[2318870.197] (II) intel(0): 0x00f7f000-0x0fffffff: DRI memory manager (246276 kB)

[2318870.197] (II) intel(0): BO memory allocation layout:

[2318870.197] (II) intel(0): 0x00f7f000: start of memory manager

[2318870.197] (II) intel(0): 0x10000000: end of memory manager

这样就能很方便的判断显卡显存大小了。

指定 KMS 分辨率

可以通过 DRM 模块参数指定 Kernel Mode Setting(KMS)的 EDID 分辨率：

Linux kernel 4.15 以后的 kernel：

drm.edid_firmware=edid/800x600.bin

其它 kernel：

drm_kms_helper.edid_firmware=edid/800x600.bin

kernel 中只包含了固定几种分辨率的 EDID 固件，自定义分辨率的固件需要放到 /lib/firmware 目录下。