On Fri, 29 Sep 2017 09:06:16 +0000 David Laight <David.Laight@xxxxxxxxxx> wrote: > > The correct names used in the new specification for the 4 speeds that can be supported by a USB 3 > > interface are: . > > I think I'd add the speed itself as well. > > David I was reffering mostly to the identifiers and comments used in the kernel source code. When the speeds are displayed to a user, e.g. in log messages or in the lsusb output, you are of course right, the numeric speeds should also be shown. Nevertheless, there is a problem with that. The correct speeds would be: "Gen 1x1 (4 Gb/s)", "Gen 1x2 (8 Gb/s)", "Gen 2x1 (10 Gb/s)", and "Gen 2x2 (20 Gb/s)". But we are forced to show "Gen 1x1 (5 Gb/s)", because this is what most users expect. There is a stupid tradition started by someone at Intel, I suppose from marketing, who had the mean idea of presenting SATA 1.0 as 1.5 Gb/s and PCIe 1.0 as 2.5 Gb/s. Before that, nobody thought that it would be right to present, e.g. Gigabit Ethernet as having a speed of 1.25 Gb/s. This deceitful method was used since then for all SATA and SAS, and also for PCIe 2.0 and for USB 3.0. In my opinion, we should display the USB 3 speeds so: "Gen 1x1 (5 Gb/s)", "Gen 1x2 (8 Gb/s)", "Gen 2x1 (10 Gb/s)", and "Gen 2x2 (20 Gb/s)". While this might confuse some users about why Gen 1x2 is not shown as having a double speed, I believe that the confusion created by seeing "Gen 1x2 (10 Gb/s)", i.e. as having the same speed as "Gen 2x1" will be worse, because the users would be fooled in believing that a "Gen 1x2" device is worth the same money as a "Gen 2x1" device, when in fact the latter is 25% faster. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
