On Thu, Dec 8, 2016 at 10:02 AM, Johan Hovold <johan@xxxxxxxxxx> wrote: > On Thu, Dec 08, 2016 at 04:41:44AM -0800, Russell Senior wrote: >> >>>>> "Johan" == Johan Hovold <johan@xxxxxxxxxx> writes: >> >> [...] >> >> Johan> Ok, and you were using a terminal program such as minicom that >> Johan> properly configures the port for say 8-bit words? >> >> I was using GNU screen, which I don't specifically configure to be >> 8-bits, but I retried with minicom and specifically set a different byte >> size (non-8) and then set it back to 8, and saw the same 5-bit like >> behavior. > > Ok, try sticking to minicom for any further tests just to be sure. > >> Johan> [...] But if I configure the port for 5-bit words, I get the >> Johan> exact sequence you describe (i.e. the three most-significant bits >> Johan> are masked out). >> >> Johan> So my guess is that either you are not configuring the port >> Johan> correctly (and are using the default settings), or the driver >> Johan> fails to configure the port (and you are also stuck with the >> Johan> default settings). >> >> Johan> This may be a bit of long shot (or maybe not) but could you try >> Johan> the below patch on top of usb-next as well? [...] >> >> Your patch seems to have fixed it! Yay! > > Interesting. I dug through the archives and found a report from Eddi De > Pieri which seems to have hit the same issue: > > https://lkml.kernel.org/r/CAKdnbx7GTH3K7eGtQ==wh=Kb74EA_eGpii0h8HXxOkLjnhhfPw@xxxxxxxxxxxxxx > > The weird part is I appear to have the same device, and it works fine > without that change. > > Could you try and just commenting out that register write in a mainline > kernel (or my usb-linus branch) to make sure the changes in -next did > not cause the issues you still see when connected to a pl2303. Okay, I built your usb-linus 46490c347df406b3368680dd911620e52dc7bfa4 with the line: r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); commented out. More precisely: diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index f139488..928966a 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -214,7 +214,7 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) if (r < 0) goto out; - r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); + // r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); if (r < 0) goto out; Loopback works, and also interoperates with pl2303 (through a null modem adapter). > > Are you using minicom on both ends with 115200 8N1 which appears to > work reliably, by the way? Yes, I'm running minicom on both ends. -- 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
