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: [BUG] mt76x0u: Probing issues on Raspberry Pi 3 B+ From: Stanislaw Gruszka Message-Id: <20190218150303.GD9602@redhat.com> Date: Mon, 18 Feb 2019 16:03:03 +0100 To: Felix Fietkau Cc: Stefan Wahren , Lorenzo Bianconi , Alan Stern , Doug Anderson , Minas Harutyunyan , USB list , linux-wireless List-ID: T24gTW9uLCBGZWIgMTgsIDIwMTkgYXQgMDM6NDM6MjZQTSArMDEwMCwgRmVsaXggRmlldGthdSB3 cm90ZToKPiBPbiAyMDE5LTAyLTE4IDE0OjUyLCBTdGFuaXNsYXcgR3J1c3prYSB3cm90ZToKPiA+ IE9uIFNhdCwgRmViIDE2LCAyMDE5IGF0IDA4OjE3OjA3UE0gKzAxMDAsIFN0ZWZhbiBXYWhyZW4g d3JvdGU6Cj4gPj4gdGhpcyBpcyBhIG1pc3VuZGVyc3RhbmRpbmcuIFRoZSB3YXJuaW5nIGlzIGFi b3V0IG1lbW9yeSBhbGlnbm1lbnQgdG8gMzIgYml0IGFkZHJlc3Nlcywgbm90IGFib3V0IHBhZ2Ug YWxpZ25tZW50LiBUaGlzIGlzIGEgdHlwaWNhbCBBUk0gcmVzdHJpY3Rpb24uIE1heWJlIHdlIG5l ZWQgdG8gbWFrZSBzdXJlIGluIG10NzYgdGhhdCB0aGUgRE1BIGJ1ZmZlciBuZWVkcyB0byBiZSBh bGlnbmVkLiBCdXQgaXQncyBhbHNvIHBvc3NpYmxlIHRoYXQgdGhlIHdhcm5pbmcgaXNuJ3QgdGhl IHJvb3QgY2F1c2Ugb2Ygb3VyIHByb2JsZW0uCj4gPj4gCj4gPiAKPiA+IEkgc2VlLCBpdCBuZWVk cyA0IGJ5dGVzIGFsaWdubWVudCAuIFRoZXJlIGlzIGFscmVhZHkgZHdjMiBjb2RlIGNoZWNrcwo+ ID4gdGhhdCBhbmQgYWxsb2NhdGUgbmV3IGJ1ZmZlciBpZiB0aGUgYWxpZ25tZW50IGlzIG5vdCBy aWdodDoKPiA+IGR3YzJfYWxsb2NfZG1hX2FsaWduZWRfYnVmZmVyKCksIGJ1dCBpdCBkb2VzIG5v dGhpbmcgaWYgdXJiLT5zZwo+ID4gaXMgbm90IE5VTEwuIEkgdGhvdWdodCBtdDc2dXNiIGFscmVh ZHkgcHJvdmlkZSBhbGlnbmVkIGJ1ZmZlcnMsIGJ1dAo+ID4gbG9va3MgaXQgZG9lcyBub3QgZm9y IG9uZSBUWCBzcGVjaWFsIGNhc2UsIHdoaWNoIGFyZSBQUk9CRSBSRVFVRVNUCj4gPiBmcmFtZXMu IE90aGVyIGZyYW1lcyBhcmUgYWxpZ25lZCBieSBpbnNlcnRpbmcgTDIgaGVhZGVyIHBhZC4gT25l Cj4gPiBzb2x1dGlvbiBmb3IgdGhpcyB3b3VsZCBiZSBqdXN0IHN1Ym1pdCB1cmIgd2l0aCAgTlVM TCBzZyAoc2FtZSBhcwo+ID4gTG9yZW56bydzIHBhdGNoZXMgZG8sIGJ1dCBzdGlsbCBhbGxvY2F0 aW5nIGJ1ZmZlcnMgdmlhIGJ1Zi0+c2cpLAo+ID4gYnV0IEkgdGhpbmssIHlvdSBoYXZlIHJpZ2h0 LCB3ZSBzaG91bGQgcHJvdmlkZSA0IGJ5dGVzIGFsaWduZWQgYnVmZmVycwo+ID4gYnkgZGVmYXVs dCBhcyBvdGhlciBETUEgaGFyZHdhcmUgbWF5IHJlcXVpcmUgdGhhdC4gSSdtIGF0dGFjaGluZyB5 ZXQKPiA+IGFub3RoZXIgcGF0Y2ggdG8gdGVzdCwgd2hpY2ggZml4IHVwIGFsaWdubWVudCBmb3Ig UFJPQkUgUkVRVUVTVCBmcmFtZXMuCj4gVGhpcyBhcHByb2FjaCBsb29rcyBjb21wbGV0ZWx5IHdy b25nIHRvIG1lLiBNTUlPIGJhc2VkIGhhcmR3YXJlIGRvZXMgbm90Cj4gbmVlZCA0LWJ5dGUgYWxp Z25lZCBidWZmZXJzIGF0IGFsbCwgb3RoZXIgVVNCIGNvbnRyb2xsZXJzIGRvIG5vdCBuZWVkCj4g dGhpcyBlaXRoZXIuCj4gQXMgTG9yZW56byBhbHJlYWR5IHBvaW50ZWQgb3V0LCByZS1hbGlnbmlu ZyB0aGUgYnVmZmVyIGlzICp2ZXJ5Kgo+IGV4cGVuc2l2ZSwgc28gd2Ugc2hvdWxkIG5vdCBkbyB0 aGlzIGluIHRoZSBkcml2ZXIganVzdCB0byB3b3JrIGFyb3VuZAo+IHF1aXJrcyBpbiBhIHBhcnRp Y3VsYXIgVVNCIGhvc3QgZHJpdmVyLgoKSSBkZWNpZGVkIHRvIHRoaXMgcGF0Y2ggYmVjYXVzZSBJ IHRob3VnaHQgc29tZSBvdGhlciBVU0IgJiBNTUlPIERNQQpwbGF0Zm9ybXMgbWlnaHQgYWxzbyBy ZXF1aXJlIHRoaXMgYWxpZ25tZW50LiBCdXQgaXQgd2FzIG5ldmVyIHRyaWdnZXJlZAppbiBNTUlP IGJlY2F1c2Ugb24gdGhvc2UgbXQ3NiBpcyB1c2VkIGluIEFQIG1vZGUsIGhlbmNlIG5vIFBST0JF ClJFUVVFU1QgZnJhbWVzIChhbmQgc2NhbiBjYW4gYmUgcGFzc2l2ZSBvbiBTVEEgbW9kZSkuCgo+ IFRoZSB3YXkgSSBzZWUgaXQsIHdlIGhhdmUgdHdvIGNob2ljZXMuCj4gMS4gRml4IGR3YzIgdG8g ZG8gaXRzIGFsaWdubWVudCBxdWlyayBmb3IgdGhlIHVyYi0+c2cgIT0gTlVMTCBjYXNlCj4gMi4g UmVseSBvbiB1cmItPnRyYW5zZmVyX2J1ZmZlciBhbmQga2VlcCB1cmItPnNnIE5VTEwKCkkgYWdy ZWUsIGlmIHRoaXMgaXMgb25seSBuZWVkZWQgZm9yIGR3YzIuIFRob3VnaCBJIHdvdWxkIGludmVz dGlnYXRlCmlmIHRoaXMgaXMgbm90IGEgYnVnIG9uIG90aGVyIHBsYXRmb3JtcyBhcyB3ZWxsLgoK U3RhbmlzbGF3Cg== From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECA18C43381 for ; Mon, 18 Feb 2019 15:03:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1C582173C for ; Mon, 18 Feb 2019 15:03:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730942AbfBRPDJ (ORCPT ); Mon, 18 Feb 2019 10:03:09 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60976 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729905AbfBRPDJ (ORCPT ); Mon, 18 Feb 2019 10:03:09 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AF8A98E6EF; Mon, 18 Feb 2019 15:03:08 +0000 (UTC) Received: from localhost (unknown [10.40.205.59]) by smtp.corp.redhat.com (Postfix) with ESMTP id 742CF600C8; Mon, 18 Feb 2019 15:03:04 +0000 (UTC) Date: Mon, 18 Feb 2019 16:03:03 +0100 From: Stanislaw Gruszka To: Felix Fietkau Cc: Stefan Wahren , Lorenzo Bianconi , Alan Stern , Doug Anderson , Minas Harutyunyan , USB list , linux-wireless Subject: Re: [BUG] mt76x0u: Probing issues on Raspberry Pi 3 B+ Message-ID: <20190218150303.GD9602@redhat.com> References: <20190212093035.GB12906@redhat.com> <404607590.373282.1550126997144@email.ionos.de> <20190214092530.GA17273@redhat.com> <878a7160-2e91-d057-6d27-c6b9d85f700e@i2se.com> <20190215071226.GA2372@redhat.com> <1411983628.668277.1550315118443@email.ionos.de> <20190216140739.GA2236@redhat.com> <2009016263.528260.1550344627996@email.ionos.de> <20190218135247.GA9602@redhat.com> <0e29e99a-6ed4-40fe-1f38-30f1b5530a16@nbd.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0e29e99a-6ed4-40fe-1f38-30f1b5530a16@nbd.name> User-Agent: Mutt/1.8.3 (2017-05-23) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Mon, 18 Feb 2019 15:03:09 +0000 (UTC) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On Mon, Feb 18, 2019 at 03:43:26PM +0100, Felix Fietkau wrote: > On 2019-02-18 14:52, Stanislaw Gruszka wrote: > > On Sat, Feb 16, 2019 at 08:17:07PM +0100, Stefan Wahren wrote: > >> this is a misunderstanding. The warning is about memory alignment to 32 bit addresses, not about page alignment. This is a typical ARM restriction. Maybe we need to make sure in mt76 that the DMA buffer needs to be aligned. But it's also possible that the warning isn't the root cause of our problem. > >> > > > > I see, it needs 4 bytes alignment . There is already dwc2 code checks > > that and allocate new buffer if the alignment is not right: > > dwc2_alloc_dma_aligned_buffer(), but it does nothing if urb->sg > > is not NULL. I thought mt76usb already provide aligned buffers, but > > looks it does not for one TX special case, which are PROBE REQUEST > > frames. Other frames are aligned by inserting L2 header pad. One > > solution for this would be just submit urb with NULL sg (same as > > Lorenzo's patches do, but still allocating buffers via buf->sg), > > but I think, you have right, we should provide 4 bytes aligned buffers > > by default as other DMA hardware may require that. I'm attaching yet > > another patch to test, which fix up alignment for PROBE REQUEST frames. > This approach looks completely wrong to me. MMIO based hardware does not > need 4-byte aligned buffers at all, other USB controllers do not need > this either. > As Lorenzo already pointed out, re-aligning the buffer is *very* > expensive, so we should not do this in the driver just to work around > quirks in a particular USB host driver. I decided to this patch because I thought some other USB & MMIO DMA platforms might also require this alignment. But it was never triggered in MMIO because on those mt76 is used in AP mode, hence no PROBE REQUEST frames (and scan can be passive on STA mode). > The way I see it, we have two choices. > 1. Fix dwc2 to do its alignment quirk for the urb->sg != NULL case > 2. Rely on urb->transfer_buffer and keep urb->sg NULL I agree, if this is only needed for dwc2. Though I would investigate if this is not a bug on other platforms as well. Stanislaw