From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [v7] cdc-acm: fix abnormal DATA RX issue for Mediatek Preloader. From: Oliver Neukum Message-Id: <1545319724.5084.3.camel@suse.com> Date: Thu, 20 Dec 2018 16:28:44 +0100 To: Johan Hovold , Macpaul Lin Cc: Andrey Arapov , Lars Melin , Greg Kroah-Hartman , Mediatek WSD Upstream , linux-usb@vger.kernel.org, stable@vger.kernel.org List-ID: T24gTWksIDIwMTgtMTItMTkgYXQgMTA6MDAgKzAxMDAsIEpvaGFuIEhvdm9sZCB3cm90ZToKPiBP biBXZWQsIERlYyAxOSwgMjAxOCBhdCAxMjoxMTowM1BNICswODAwLCBNYWNwYXVsIExpbiB3cm90 ZToKPiA+IE1lZGlhdGVrIFByZWxvYWRlciBpcyBhIHByb3ByaWV0YXJ5IGVtYmVkZGVkIGJvb3Qg bG9hZGVyIGZvciBsb2FkaW5nCj4gPiBMaXR0bGUgS2VybmVsIGFuZCBMaW51eCBpbnRvIGRldmlj ZSBEUkFNLgo+ID4gCj4gPiBUaGlzIGJvb3QgbG9hZGVyIGFsc28gaGFuZGxlIGZpcm13YXJlIHVw ZGF0ZS4gTWVkaWF0ZWsgUHJlbG9hZGVyIHdpbGwgYmUKPiA+IGVudW1lcmF0ZWQgYXMgYSB2aXJ0 dWFsIENPTSBwb3J0IHdoZW4gdGhlIGRldmljZSBpcyBjb25uZWN0ZWQgdG8gV2luZG93cwo+ID4g b3IgTGludXggT1MgdmlhIENEQy1BQ00gY2xhc3MgZHJpdmVyLiBXaGVuIHRoZSBVU0IgZW51bWVy YXRpb24gaGFzIGJlZW4KPiA+IGRvbmUsIE1lZGlhdGVrIFByZWxvYWRlciB3aWxsIHNlbmQgb3V0 IGhhbmRzaGFrZSBjb21tYW5kICJSRUFEWSIgdG8gUEMKPiA+IGFjdGl2ZWx5IGluc3RlYWQgb2Yg d2FpdGluZyBjb21tYW5kIGZyb20gdGhlIGRvd25sb2FkIHRvb2wuCj4gPiAKPiA+IFNpbmNlIExp bnV4IDQuMTIsIHRoZSBjb21taXQgInR0eTogcmVzZXQgdGVybWlvcyBzdGF0ZSBvbiBkZXZpY2UK PiA+IHJlZ2lzdHJhdGlvbiIgKDkzODU3ZWRkOTgyOWUxNDRhY2I2YzdlNzJkNTkzZjZlMDFhZWFk NjYpIGNhdXNlcyBNZWRpYXRlawo+ID4gUHJlbG9hZGVyIHJlY2VpdmluZyBzb21lIGFibm9yYW1s IGNvbW1hbmQgbGlrZSAiUkVBRFlYWCIgYXMgaXQgc2VudC4KPiA+IFRoaXMgd2lsbCBiZSByZWNv Z25pemVkIGFzIGFuIGluY29ycmVjdCByZXNwb25zZS4gVGhlIGJlaGF2aW9yIGNoYW5nZQo+ID4g YWxzbyBjYXVzZXMgdGhlIGRvd25sb2FkIGhhbmRzaGFrZSBmYWlsLiBUaGlzIGNoYW5nZSBvbmx5 IGFmZmVjdHMKPiA+IHN1YnNlcXVlbnQgY29ubmVjdHMgaWYgdGhlIHJlY29ubmVjdGVkIGRldmlj ZSBoYXBwZW5zIHRvIGdldCB0aGUgc2FtZSBtaW5vcgo+ID4gbnVtYmVyLgo+ID4gCj4gPiBCeSBk aXNhYmxpbmcgdGhlIEVDSE8gdGVybWlvcyBmbGFnIGNvdWxkIGF2b2lkIHRoaXMgcHJvYmxlbS4g SG93ZXZlciwgaXQKPiA+IGNhbm5vdCBiZSBkb25lIGJ5IHVzZXIgc3BhY2UgY29uZmlndXJhdGlv biB3aGVuIGRvd25sb2FkIHRvb2wgb3Blbgo+ID4gL2Rldi90dHlBQ00wLiBUaGlzIGlzIGJlY2F1 c2UgdGhlIGRldmljZSBydW5uaW5nIE1lZGlhdGVrIFByZWxvYWRlciB3aWxsCj4gPiBzZW5kIGhh bmRzaGFrZSBjb21tYW5kICJSRUFEWSIgaW1tZWRpYXRlbHkgb25jZSB0aGUgQ0RDLUFDTSBkcml2 ZXIgaXMKPiA+IHJlYWR5Lgo+ID4gCj4gPiBUaGlzIHBhdGNoIHdhbnRzIHRvIGZpeCBhYm92ZSBw cm9ibGVtIGJ5IGludHJvZHVjaW5nICJESVNBQkxFX0VDSE8iCj4gPiBwcm9wZXJ0eSBpbiBkcml2 ZXJfaW5mby4gV2hlbiBNZWRpYXRlayBQcmVsb2FkZXIgaXMgY29ubmVjdGVkLCB0aGUKPiA+IENE Qy1BQ00gZHJpdmVyIGNvdWxkIGRpc2FibGUgRUNITyBmbGFnIGluIHRlcm1pb3MgdG8gYXZvaWQg dGhlIHByb2JsZW0uCj4gPiAKPiA+IFNpZ25lZC1vZmYtYnk6IE1hY3BhdWwgTGluIDxtYWNwYXVs LmxpbkBtZWRpYXRlay5jb20+Cj4gPiBDYzogc3RhYmxlQHZnZXIua2VybmVsLm9yZwo+ID4gLS0t Cj4gPiBDaGFuZ2VzIGZvciB2MjoKPiA+ICAtIE1vdmUgcXVpcmtzIHRlc3Rpbmcgb2YgRElTQUJM RV9FQ0hPIGZsYWcgaW50byBhY21fdHR5X2luc3RhbGwoKS4KPiA+ICAtIENoYW5nZSBxdWlya3Mg dGVzdGluZyBpbnRvIGJpdHdpc2UgY29tcGFyaXNvbi4KPiA+IENoYW5nZXMgZm9yIHYzOgo+ID4g IC0gUmVwbGFjZSBxdWlya3MgdGVzdGluZyBmcm9tIGluaXRfdGVybWlvcyB0byB0dHktPnRlcm1p b3MuCj4gPiAgLSBSZW1vdmUgcGFyZW50aGVzaXMgZm9yIEVDSE8gZmxhZy4KPiA+IENoYW5nZXMg Zm9yIHY0Ogo+ID4gIC0gRHJvcCBxdWlya3MgdmFyaWJsZSB0byBzaW1wbGlmeSB0aGUgcGF0Y2gu Cj4gPiAgLSBNb3ZlIHRlcm1pb3Mgb3BlcmF0aW9uIHJpZ2h0IGFmdGVyIHRoZSBkcml2ZXJfZGF0 YSBoYXMgYmVlbiBpbnN0YWxsZWQuCj4gPiAgLSBXcml0ZSBnZW5lcmFsIHN0eWxlIGNvbW1lbnQg Zm9yIHN1cHByZXNzaW5nIGluaXRpYWwgZWNob2luZy4gCj4gPiBDaGFuZ2VzIGZvciB2NToKPiA+ ICAtIEZpeDogdGVybWlvcyBvcGVyYXRpb24gcmlnaHQgYWJvdmVyIHRoZSBkcml2ZXJfZGF0YSBo YXMgYmVlbiBpbnN0YWxsZWQuCj4gPiAgLSBVcGRhdGUgY29tbWl0IGNvbW1lbnQgYWJvdXQgdGhp cyBwYXRjaCBhZmZlY3RzIHRoZSByZWNvbm5lY3RlZCBkZXZpY2UKPiA+ICAgIHdoaWNoIGdldCB0 aGUgc2FtZSBtaW5vciBudW1iZXJzLgo+ID4gQ2hhbmdlcyBmb3IgdjY6Cj4gPiAgLSBVcGRhdGUg VklEL1BJRDoweDBlOGQvMHgwMDAzIGFzIE1lZGlhdGVrIEluYyBCUk9NLgo+ID4gIC0gVXBkYXRl IFZJRC9QSUQ6MHgwZThkLzB4MjAwMCBhcyBNZWRpYXRlayBJbmMgUHJlbG9hZGVyLgo+ID4gQ2hh bmdlcyBmb3Igdjc6Cj4gPiAgLSBLZWVwIFZJRC9QSUQ6MHgwZThkLzB4MDAwMyB1bmNoYW5nZWQg YmVjYXVzZSBvZiAyIGRpZmZlcmVudCBVTklPTgo+ID4gICAgZGVzY3JpcHRvciBpbXBsZW1lbnRh dGVkIGluIE1lZGlhdGVrIEluYyBCUk9NIChNVDY1ODkvTVQ2NzY1KS4KPiAKPiBSZXZpZXdlZC1i eTogSm9oYW4gSG92b2xkIDxqb2hhbkBrZXJuZWwub3JnPgpBY2tlZC1ieTogT2xpdmVyIE5ldWt1 bSA8b25ldWt1bUBzdXNlLmNvbT4K From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:55988 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725440AbeLTP33 (ORCPT ); Thu, 20 Dec 2018 10:29:29 -0500 Message-ID: <1545319724.5084.3.camel@suse.com> Subject: Re: [PATCH v7] cdc-acm: fix abnormal DATA RX issue for Mediatek Preloader. From: Oliver Neukum To: Johan Hovold , Macpaul Lin Cc: Andrey Arapov , Lars Melin , Greg Kroah-Hartman , Mediatek WSD Upstream , linux-usb@vger.kernel.org, stable@vger.kernel.org Date: Thu, 20 Dec 2018 16:28:44 +0100 In-Reply-To: <20181219090008.GR20658@localhost> References: <1544671676-23912-1-git-send-email-macpaul.lin@mediatek.com> <1545192663-5721-1-git-send-email-macpaul.lin@mediatek.com> <20181219090008.GR20658@localhost> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: On Mi, 2018-12-19 at 10:00 +0100, Johan Hovold wrote: > On Wed, Dec 19, 2018 at 12:11:03PM +0800, Macpaul Lin wrote: > > Mediatek Preloader is a proprietary embedded boot loader for loading > > Little Kernel and Linux into device DRAM. > > > > This boot loader also handle firmware update. Mediatek Preloader will be > > enumerated as a virtual COM port when the device is connected to Windows > > or Linux OS via CDC-ACM class driver. When the USB enumeration has been > > done, Mediatek Preloader will send out handshake command "READY" to PC > > actively instead of waiting command from the download tool. > > > > Since Linux 4.12, the commit "tty: reset termios state on device > > registration" (93857edd9829e144acb6c7e72d593f6e01aead66) causes Mediatek > > Preloader receiving some abnoraml command like "READYXX" as it sent. > > This will be recognized as an incorrect response. The behavior change > > also causes the download handshake fail. This change only affects > > subsequent connects if the reconnected device happens to get the same minor > > number. > > > > By disabling the ECHO termios flag could avoid this problem. However, it > > cannot be done by user space configuration when download tool open > > /dev/ttyACM0. This is because the device running Mediatek Preloader will > > send handshake command "READY" immediately once the CDC-ACM driver is > > ready. > > > > This patch wants to fix above problem by introducing "DISABLE_ECHO" > > property in driver_info. When Mediatek Preloader is connected, the > > CDC-ACM driver could disable ECHO flag in termios to avoid the problem. > > > > Signed-off-by: Macpaul Lin > > Cc: stable@vger.kernel.org > > --- > > Changes for v2: > > - Move quirks testing of DISABLE_ECHO flag into acm_tty_install(). > > - Change quirks testing into bitwise comparison. > > Changes for v3: > > - Replace quirks testing from init_termios to tty->termios. > > - Remove parenthesis for ECHO flag. > > Changes for v4: > > - Drop quirks varible to simplify the patch. > > - Move termios operation right after the driver_data has been installed. > > - Write general style comment for suppressing initial echoing. > > Changes for v5: > > - Fix: termios operation right abover the driver_data has been installed. > > - Update commit comment about this patch affects the reconnected device > > which get the same minor numbers. > > Changes for v6: > > - Update VID/PID:0x0e8d/0x0003 as Mediatek Inc BROM. > > - Update VID/PID:0x0e8d/0x2000 as Mediatek Inc Preloader. > > Changes for v7: > > - Keep VID/PID:0x0e8d/0x0003 unchanged because of 2 different UNION > > descriptor implementated in Mediatek Inc BROM (MT6589/MT6765). > > Reviewed-by: Johan Hovold Acked-by: Oliver Neukum