Differences

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--- doc:appunti:hardware:x96_mini [2023/10/22 22:23] – [Connecting an external USB 2.5 inches hard disk] niccolo
+++ doc:appunti:hardware:x96_mini [2023/10/22 23:32] (current) – [Ports and connectors] niccolo
@@ Line 32: / Line 32: @@
 {{.:amlogic:x96mini-ports2.jpg?direct&400|USB, SD card}}
-One USB port is **white** in color, so it should be an **USB 1.x**, the **black** USB port should be instead an **USB 2.0 Hi-Speed**.
+One USB port is **white** in color, so it should be an **USB 1.x**, the **black** USB port should be instead an **USB 2.0 Hi-Speed**. But measuring the read/write performance of an USB external disk, it turned out that both the ports are 2.0 Hi-Speed.
 ====== First boot using the toothpick trick ======
@@ Line 239: / Line 240: @@
 ====== Connecting a 2.5" hard disk via the USB ======
+I connected an **external hard disk**; specifically it is a Toshiba MQ04UBF100, 2.5 inches hard drive, SATA 3.0, **1 Tb**, using an **USB 3.0** interface.
-Disk performance
+At first I tried to power the hard disk directly from the USB port of the X96 mini, but it turned out that the USB port **does not provide enough power**. The hard disk suddendly and randomly **disconnect and re-connect** with no reason. Here it is the relevant kernel messages displayed by the **dmesg** tool:
+<code>
+[  526.677574@2]- usb 1-2: USB disconnect, device number 2
+[  526.678631@2]- blk_update_request: I/O error, dev sda, sector 903710960
+...
+[  526.942573@3]- EXT4-fs error (device sda1): ext4_journal_check_start:56: Detected aborted journal
+[  526.942578@3]- EXT4-fs (sda1): Remounting filesystem read-only
+[  526.942585@3]- EXT4-fs (sda1): previous I/O error to superblock detected
+[  526.942612@3]d Buffer I/O error on dev sda1, logical block 0, lost sync page write
+[  526.983449@2]- sd 0:0:0:0: [sda] Synchronizing SCSI cache
+[  526.997855@2]- sd 0:0:0:0: [sda] Synchronize Cache(10) failed: Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK
+[  527.796877@2]- usb 1-2: new high-speed USB device number 4 using xhci-hcd
+[  527.938266@2]- usb 1-2: New USB device found, idVendor=0480, idProduct=0901
+[  527.938278@2]- usb 1-2: New USB device strings: Mfr=2, Product=3, SerialNumber=1
+[  527.938282@2]- usb 1-2: Product: External USB 3.0
+</code>
+Typically a 2.5" drive requires about **1 A** at startup and about **500 mA** at read/write average. It is likely that the X96 Mini's circuitry provides USB ports with barely the minimum required by the USB 2.0 standard, which is **5 V, 500 mA**, regardless the rating of the power supply (mine was rated 4A).
+Fortunately there is a solution: to use an **externally powered USB hub**. I purchased a **4 ports USB 3.0 hub** with an USB Type-C connector to supply it with power. In this new configuration a **3 A** power supply provides the power to the USB hub. The external hard disk is connected to one of the 4 ports of the hub and it takes its power from this. The X96 Mini is connected to the hub cable through the USB A connector and it takes the power from the hub too. The original power supply is not longer required and **all the system is powered by only one power supply**.
+I measured the disk performance on both the two USB ports (the white one and the black one), they measured exactly the same transfer rate. For the test I used the **hdparm** tool:
+<code>
+hdparm -t /dev/sda
+</code>
 <code>
-CoreELEC:~ # hdparm -t /dev/sda
+Timing buffered disk reads: 102 MB in  3.03 seconds =  33.71 MB/sec
-/dev/sda:
- Timing buffered disk reads:  92 MB in  3.05 seconds =  30.14 MB/sec
 </code>
+This is about **270 Mbit/s**, which is near the 280 Mbps of the USB 2.0 //High Speed// specifications. This means that both the USB ports are actually USB 2.0.