CN114741035A - The reading method of the EDID data of the Linux system adapting to the whole Loongson machine - Google Patents

Abstract

The invention relates to a method for reading EDID data of a Linux system adapted to a complete Loongson machine. Loongson is Loongson 2K1000, and the reading method is as follows: the display driver reads the EDID data from the eeprom; or, when the display driver reads the EDID data from the eeprom If the EDID data is not read, the EDID data is read from the Linux system; or, when the display driver does not read the EDID data from the eeprom and the Linux system, the display driver reads the EDID data from the open source firmware PMON. The main purpose of the present invention is to provide a method for reading the EDID data of a Linux system adapted to the whole Loongson machine, so as to solve the problem that the display driver cannot read the EDID data when the hardware manufacturer does not consider eeprom.

Description

The reading method of the EDID data of the Linux system adapting to the whole Loongson machine

technical field

The invention relates to a method for reading EDID data, in particular to a method for reading EDID data of a Linux system adapting to a complete Loongson machine.

Background technique

Extended Display Identification Data (EDID), Chinese is extended display identification data. It is a standard for display identification data formulated by VESA when it develops the DDC display data channel communication protocol. The EDID is stored in the DDC memory of the monitor. When the computer host is connected to the monitor, the computer host will read the stored EDID data in the DDC memory of the monitor through the DDC channel.

On the Loongson 2K1000 platform, eeprom (erasable electronic programmable read-only memory) is hung on the i2c bus, and EEID data is stored in the eeprom.

If the EDID data is stored in the eeprom, the display driver reads the EDID data from the i2c bus address mounted by the eeprom. The display driver reads the edid data stored in the eeprom through the i2c bus.

If the hardware manufacturer does not consider the eeprom device (this device is used to store EDID data) when designing the hardware, there is a problem that the display driver cannot read the EDID data from the eeprom.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a method for reading the EDID data of a Linux system adapted to the whole Loongson machine, so as to solve the problem that when the hardware manufacturer does not consider eeprom, the display driver can still read the EDID data.

In order to accomplish the above purpose, the present invention provides a method for reading the EDID data of a Linux system adapting to a complete Loongson machine, and the complete Loongson machine is Loongson 2K1000, and the reading method is as follows:

Make the display driver read EDID data from eeprom;

Or, when the display driver does not read the EDID data from the eeprom, read the EDID data pre-installed in the Linux system from the Linux system;

Or, when the display driver does not read the EDID data from the eeprom and the Linux system, the display driver reads the EDID data preinstalled in the open source firmware PMON from the open source firmware PMON.

Preferably, the storage method of EDID data in the Linux system is:

S10: Install the edid tool package in the Linux system;

S20: Generate an edid.bin file with a specified resolution, where the specified resolution is the best resolution currently displayed;

S30: Create an edid directory folder for storing EDID data;

S40: utilize the edid.bin file in step S20 to generate new EDID data, and copy these EDID data to the edid directory folder in step S30;

S50: Modify the boot boot parameters, and directly modify the system boot file on the Loongson open source firmware PMON platform;

S60: Confirm whether the kernel configuration item is turned on, if turned on, complete the storage of EDID data, if not turned on, turn on the kernel configuration item, update the kernel, and replace it with the target system.

Further preferably, in step S40, generating new EDID data is obtained by the following methods:

By loading the fake edid.bin file with the specified resolution from the Linux system directory, and then generating new EDID data through the get-edid tool or the monitor-get-edid tool;

Or, copy directly from the existing EDID data in the edid-generator software.

Further preferably, in step S50, the method of modifying the system boot file is as follows:

Add the following parameters to the system boot file:

GRUB_CMDLINE_LINUX_DEFAULT="drm_kms_helper.edid_firmware=edid/display resolution value.bin quiet", after the modification is completed, update the gruby boot.

Preferably, the method for reading EDID data in the open source firmware PMON is as follows:

Read all hardware configuration data from the open source firmware PMON, and confirm whether there is a node /soc/edid@0 in the read hardware configuration data. If there is a node /soc/edid@0, continue to confirm whether there is a node for storing The edid-buf child node of the EDID data, if there is an edid-buf child node, read the EDID data, if there is no edid-buf child node, read the EDID data and return if it fails;

If the node /soc/edid@0 does not exist, it will fail to read the EDID data and return.

The beneficial effects of the present invention are:

The present invention provides another method for the display driver to read EDID data. First, the EDID data is pre-stored in the disk partition of the Linux system and/or the open source firmware PMON, so that when the display driver cannot read the EDID data from the eeprom , the display driver can read the pre-stored EDID data from the Linux system partition, or, when the EDID data cannot be read in the Linux system, the display driver can also read the EDID data from the open source firmware PMON.

Description of drawings

The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic diagram of the work flow of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Many specific details are set forth in the following description to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein, and those skilled in the art can do so without departing from the connotation of the present invention. Similar promotion, therefore, the present invention is not limited by the specific embodiments disclosed below.

As shown in FIG. 1 , this embodiment provides a method for reading EDID data of a Linux system adapted to a complete Loongson machine, which is a Loongson 2K1000. The read method is as follows:

First, make the display driver read the EDID data from the eeprom; and if the display driver cannot read the EDID data from the eeprom, the display driver can read the EDID data preinstalled in the Linux system from the Linux system. In addition, when the display driver cannot read the EDID data from neither the eeprom nor the Linux system, the display driver can read the PMONEDID data pre-installed in the open source firmware from the open source firmware PMON.

Specifically, in this embodiment, the storage and reading methods of EDID data in the Linux system are:

S10: edid installation tool software package in the Linux system, such as read-edid or monitor-edid tool software package; in this embodiment, read-edid is used as an application example: the command to install the tool software package read-edid is as follows:

$ sudo apt-get install read-edid.

S20: Generate an edid.bin file with a specified resolution, where the specified resolution is the best resolution currently displayed. In this example, the best resolution of 1600x1050 is used as an example:

$sudo get-edid>1600x1050.bin

The detailed content of the edid.bin file can be confirmed by edid-decode.

S30: Create an edid directory folder for storing EDID data; the specific operation methods are as follows:

$ sudo mkdir /usr/lib/firmware/edid.

S40: use the edid.bin file in step S20 to generate new EDID data, and copy these EDID data to the edid directory folder in step S30; the operation mode is as follows:

$ sudo cp 1600x1050.bin /usr/lib/firmware/edid.

In this step, the newly generated EDID data is obtained as follows:

By loading the fake specified resolution edid.edid file (edid.bin, the suffix is .bin file) from the Linux system directory (/usr/lib/firmware/edid/), and then through the get-edid tool or monitor-get -edid tool generation. In addition, the newly generated EDID data can also directly copy the existing data in the edid-generator software to the target directory under the firmware (usually /usr/lib/firmware/edid/).

In addition, if the data content in the edid file is wrong, it can be modified by editing software (Phoenix+EDID+Designer+display EDID editor).

S50: Modify the boot parameters, and directly modify the system boot (path: /boot/boot.cfg) file on the Loongson open source firmware PMON platform; the specific operations are as follows:

$ sudo edit /etc/default/grub.

Add the following parameters to the /boot/boot.cfg file:

GRUB_CMDLINE_LINUX_DEFAULT="drm_kms_helper.edid_firmware=edid/(display resolution value).bin quiet", the resolution value used here is 1600x1050,

Therefore, the added parameters are:

GRUB_CMDLINE_LINUX_DEFAULT="drm_kms_helper.edid_firmware=edid/1600x1050.bin quiet";

In addition, if the operator is not sure whether the above operation is accurate, you can add debugging parameters, such as drm.debug=14 and video=VGA-1:e----------------- ----@VGA-1, after adding drm.debug=14, look at the output log to determine, the output result may also be other names, which is determined according to the actual situation. In addition, you can also use the edid-decode command to view the edid binary file in the /sys/devices directory to confirm whether there is an edid binary file (including EDID format data) in the corresponding path. Finally, update the grub boot file ($sudo update-grub).

S60: Confirm whether the kernel configuration item (CONFIG_DRM_LOAD_EDID_FIRMWARE) is turned on. If it is turned on, the storage of EDID data is completed. If it is not turned on, turn on the kernel configuration item, update the kernel, and replace it with the target system.

To check the edid binary file, whether the information contained in the EDID data format is valid, you can use the following command. To parse a binary file with a resolution of 1600x1050, as follows:

$parse-edid<1600x1050.bin:

parse-edid:parse-edid version 2.0.0

parse-edid: EDID checksum passed.

#EDID version 1revision 3

Section "Monitor"

#Block type:2:0 3:fc

Identifier "22T41-H-AN"

VendorName"KTC"

ModelName"22T41-H-AN"

#Block type:2:0 3:fc

#Block type:2:0 3:fd

HorizSync 15-68

VertRefresh 49-61

#Max dot clock(video bandwidth)150MHz

#DPMS capabilities:Active off:no Suspend:no Standby:no

Mode "1280x720"

#vfreq 60.000Hz, hfreq 45.000kHz

DotClock

74.250000

HTimings

1280 1390 1430 1650

VTimings

720 725 730 750

Flags"+HSync""+Vsync"

EndMode

Mode"1680x1050"#vfreq 59.883Hz,hfreq 64.674kHz

DotClock

119.000000

HTimings

1680 1728 1760 1840

VTimings

1050 1053 1059 1080

Flags"-HSync""+Vsync"

EndMode#Block type:2:0 3:fc

#Block type:2:0 3:fd

EndSection

View the startup item information command loaded by the system, and the output is similar to the following:

$cat /proc/cmdline

Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.8.0-30-genericroot=UUID=939b3111-4906-46ae-9ad7-7faa783d490d rodrm_kms_helper.edid_firmware=edid/1600x1050.bin video=VGA-1:e quiet…

Specify to load the edid file from the firmware, and the startup parameter setting method is as follows:

'drm_kms_helper.edid_firmware=edid/1600x1050.bin'

Video related parameters are introduced, the format is as follows:

video=<conn>:<xres>x<yres>[M][R][-<bpp>][@<refresh>][i][m][eDd]

<conn>:Connector,e.g.DVI-I-1,see/sys/class/drm/foravailableconnectors

<xres>x<yres>:resolution

M:compute a CVT mode?

R: reduced blanking?

-<bpp>:color depth

@<refresh>:refresh rate

i:interlaced(non-CVT mode)

m:margins?

e:output forced to on

d: output forced to off

D:digital output forced to on(e.g.DVI-I connector)

If multiple outputs, such as DVI-1 is turned on and TV-1 is turned off, the startup parameters are set as follows:

'video=DVI-1:1024x768@85video=TV-1:d'.

In this embodiment, PMON is an early BIOS firmware of Loongson, used for booting and storing hardware information, and it is written into the boot flash storage. The method of reading EDID data from open source firmware PMON is as follows: read all hardware configuration data from open source firmware PMON, confirm whether there is node /soc/edid@0 in the read hardware configuration data, if there is a node /soc/edid@0 continues to confirm whether there is an edid-buf child node for storing EDID data, if there is an edid-buf child node, read EDID data, if there is no edid-buf child node, read EDID data fails Return; if there is no node /soc/edid@0, it will fail to read EDID data and return.

Alternatively, you can also add the following way to read in the kernel code:

Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Claims (5)

1. the reading method of the EDID data of Linux system adaptation Loongson complete machine, it is characterized in that, described Loongson complete machine is Loongson 2K1000, and this reading method is as follows: Make the display driver read EDID data from eeprom; Or, when the display driver does not read the EDID data from the eeprom, the EDID data preinstalled in the Linux system is read from the Linux system; Or, when the display driver does not read the EDID data from the eeprom and the Linux system, the display driver reads the EDID data preinstalled in the open source firmware PMON from the open source firmware PMON. 2. the reading method of the EDID data of Linux system adaptation Loongson complete machine according to claim 1, is characterized in that, the storage method of described EDID data in Linux system is: S10: Install the edid tool package in the Linux system; S20: Generate an edid.bin file with a specified resolution, where the specified resolution is the best resolution currently displayed; S30: Create an edid directory folder for storing EDID data; S40: utilize the edid.bin file in step S20 to generate new EDID data, and copy these EDID data to the edid directory folder in step S30; S50: Modify the boot parameters, and directly modify the system boot file on the Loongson open source firmware PMON platform; S60: Confirm whether the kernel configuration item is turned on, if turned on, complete the storage of EDID data, if not turned on, turn on the kernel configuration item, update the kernel, and replace it with the target system. 3. the reading method of the EDID data of Linux system adaptation Loongson complete machine according to claim 2, is characterized in that, in step S40, generating new EDID data is to obtain by the following way: By loading the edid.bin file of the specified resolution from the Linux system directory, and then generating new EDID data through the get-edid tool or the monitor-get-edid tool; Alternatively, copy directly from existing EDID data in the edid-generator software. 4. the reading method of the EDID data of Linux system adaptation Loongson complete machine according to claim 2, is characterized in that, in step S50, revising system boot file mode is as follows: Add the following parameters to the system boot file: GRUB_CMDLINE_LINUX_DEFAULT="drm_kms_helper.edid_firmware=edid/display resolution value.bin quiet" After the modification is completed, update the gruby boot. 5. the reading method of the EDID data of Linux system adaptation Loongson complete machine according to claim 1, is characterized in that, in described open source firmware PMON, the method for reading EDID data is as follows: Read all hardware configuration data from the open source firmware PMON, and confirm whether there is a node /soc/edid@0 in the read hardware configuration data. If there is a node /soc/edid@0, continue to confirm whether there is a node for storing The edid-buf child node of the EDID data, if there is an edid-buf child node, read the EDID data, if there is no edid-buf child node, read the EDID data and return if it fails; If the node /soc/edid@0 does not exist, it will fail to read the EDID data and return.

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