Return-path: Received: from mail-it0-f67.google.com ([209.85.214.67]:40704 "EHLO mail-it0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934517AbeEJKbA (ORCPT ); Thu, 10 May 2018 06:31:00 -0400 Received: by mail-it0-f67.google.com with SMTP id j186-v6so2502496ita.5 for ; Thu, 10 May 2018 03:30:59 -0700 (PDT) Message-ID: <5AF41F55.4060606@sra-tohoku.co.jp> (sfid-20180510_123104_600602_A76EA0DA) Date: Thu, 10 May 2018 19:30:45 +0900 From: Taketo Kabe MIME-Version: 1.0 To: b43-dev@lists.infradead.org CC: kabe@sra-tohoku.co.jp, linux-wireless@vger.kernel.org, kvalo@codeaurora.org Subject: [PATCH v2] drivers/net/wireless/broadcom/b43: fix transmit failure when VT is switched References: <5AF2DE73.20608@sra-tohoku.co.jp> <20180509185101.0888bd7a@wiggum> In-Reply-To: <20180509185101.0888bd7a@wiggum> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: From: Taketo Kabe Fix for b43 wireless card stopping transmission when switching VTs. Setup: Using BCM4306 rev.03 chip based CardBus wireless card. IRQ is shared with yenta (cardbus bridge) and i915 (display) driver. For firmware, installed latest but dated openfwwf 5.2 (http://netweb.ing.unibs.it/~openfwwf/) How-to-reproduce: Do "ssh ", then "ls -lR /" to generate traffic, then repeatedly switch VTs by Alt-F1<>Alt-F2. Eventually (within a minute) the card stops working. You can receive traffic but no transmission. For unknown reason it doesn't occur when just generating traffic by "ssh ls -lR /". With CONFIG_B43_DEBUG=y kernel config, when it stops, the debug message shows kernel: b43-phy1 debug: Out of order TX status report on DMA ring 1. Expected 148, but got 180 The slot offset I observed so far was always 32. When err_out2 is not set to make error messages successive, the debug output will be like this: kernel: b43-phy1 debug: Out of order TX status report on DMA ring 1. Expected 116, but got 148 kernel: b43-phy1 debug: Out of order TX status report on DMA ring 1. Expected 116, but got 150 kernel: b43-phy1 debug: Out of order TX status report on DMA ring 1. Expected 116, but got 120 kernel: b43-phy1 debug: Out of order TX status report on DMA ring 1. Expected 116, but got 152 kernel: b43-phy1 debug: Out of order TX status report on DMA ring 1. Expected 116, but got 122 kernel: b43-phy1 debug: Out of order TX status report on DMA ring 1. Expected 116, but got 154 kernel: b43-phy1 debug: Out of order TX status report on DMA ring 1. Expected 116, but got 124 kernel: b43-phy1 debug: Out of order TX status report on DMA ring 1. Expected 116, but got 156 kernel: b43-phy1 debug: Out of order TX status report on DMA ring 1. Expected 116, but got 126 The TX ring alternates between 2 sequences; the ring seems to be completely confused. Controller restart is needed. Workaround(1): This problem doesn't occur when using propriatory firmware you will extract by b43-fwcutter, so it may be a bug in openfwwf firmware, as the comment in the b43_dma_handle_txstatus() suggests. I wasn't able to find a bug in the terse openfwwf code though. Workaround(2): Using "pio=1" option to not use DMA makes this problem to not occur. Description of the patch: This patch will forcibly reset the controller to make it work again. Very kludgy and doesn't look right, but the traffic will continue to flow. Changes since last edition: - Remove now unused err_out2 variable. Signed-off-by: Taketo Kabe --- diff -up ./drivers/net/wireless/broadcom/b43/dma.c.b43 ./drivers/net/wireless/broadcom/b43/dma.c --- ./drivers/net/wireless/broadcom/b43/dma.c.b43 2018-05-04 15:18:12.000000000 +0900 +++ ./drivers/net/wireless/broadcom/b43/dma.c 2018-05-10 18:46:36.000000000 +0900 @@ -1484,7 +1484,7 @@ void b43_dma_handle_txstatus(struct b43_ int slot, firstused; bool frame_succeed; int skip; - static u8 err_out1, err_out2; + static u8 err_out1; ring = parse_cookie(dev, status->cookie, &slot); if (unlikely(!ring)) @@ -1518,13 +1518,13 @@ void b43_dma_handle_txstatus(struct b43_ } } else { /* More than a single header/data pair were missed. - * Report this error once. + * Report this error, and reset the controller to + * revive operation. */ - if (!err_out2) - b43dbg(dev->wl, - "Out of order TX status report on DMA ring %d. Expected %d, but got %d\n", - ring->index, firstused, slot); - err_out2 = 1; + b43dbg(dev->wl, + "Out of order TX status report on DMA ring %d. Expected %d, but got %d\n", + ring->index, firstused, slot); + b43_controller_restart(dev, "Out of order TX"); return; } } -- kabe