Return-path: <linux-wireless-owner@vger.kernel.org>
Received: from smtp.codeaurora.org ([198.145.29.96]:54425 "EHLO
	smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1753111AbcBBIPj (ORCPT
	<rfc822;linux-wireless@vger.kernel.org>);
	Tue, 2 Feb 2016 03:15:39 -0500
From: Kalle Valo <kvalo@codeaurora.org>
To: Larry Finger <Larry.Finger@lwfinger.net>
Cc: devel@driverdev.osuosl.org, linux-wireless@vger.kernel.org,
	Johannes Berg <johannes@sipsolutions.net>,
	Stable <stable@vger.kernel.org>
Subject: Re: [PATCH] rtlwifi: Fix warning from ieee80211_get_tx_rates() when using 5G
References: <1454353134-29939-1-git-send-email-Larry.Finger@lwfinger.net>
Date: Tue, 02 Feb 2016 10:15:31 +0200
In-Reply-To: <1454353134-29939-1-git-send-email-Larry.Finger@lwfinger.net>
	(Larry Finger's message of "Mon, 1 Feb 2016 12:58:54 -0600")
Message-ID: <87zivjh6jg.fsf@kamboji.qca.qualcomm.com> (sfid-20160202_091545_083670_9B93B5E6)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Sender: linux-wireless-owner@vger.kernel.org
List-ID: <linux-wireless.vger.kernel.org>

Larry Finger <Larry.Finger@lwfinger.net> writes:

> When using a 5G-capable device with VHT rates enabled, the following
> warning results:
>
> WARNING: CPU: 3 PID: 2253 at net/mac80211/rate.c:625 ieee80211_get_tx_rates+0x22e/0x620 [mac80211]()
> Modules linked in: rtl8821ae btcoexist rtl_pci rtlwifi fuse drbg ansi_cprng ctr ccm bnep bluetooth af_packet nfs fscache vboxpci(O) vboxnetadp(O) vboxne
> tflt(O) vboxdrv(O) arc4 snd_hda_codec_generic x86_pkg_temp_thermal rtsx_pci_sdmmc mmc_core rtsx_pci_ms kvm_intel memstick iwlmvm kvm mac80211 snd_hda_intel snd_hda_cod
> ec snd_hwdep snd_hda_core irqbypass snd_pcm iwlwifi crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel aes_x86_64 snd_timer lrw gf128mul glue_h
> elper ablk_helper cryptd snd cfg80211 pcspkr serio_raw e1000e rtsx_pci lpc_ich ptp xhci_pci mfd_core pps_core xhci_hcd soundcore toshiba_acpi thermal sparse_keymap wmi
>  toshiba_bluetooth rfkill acpi_cpufreq battery ac processor dm_mod i915 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops
> drm sr_mod cdrom video button sg autofs4 [last unloaded: rtlwifi]
> CPU: 3 PID: 2253 Comm: Timer Tainted: G        W  O    4.5.0-rc1-wl+ #79
> Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.20   04/17/2014
>   ffffffffa05c4be6 ffff8802262036d8 ffffffff813d7912 0000000000000000
>   ffff880226203710 ffffffff8106bcb6 ffff8800c6831300 ffff8800c6831330
>   0000000000000000 ffff8800c683133c ffff880065923638 ffff880226203720
> Call Trace:
>   <IRQ>  [<ffffffff813d7912>] dump_stack+0x4b/0x79
>   [<ffffffff8106bcb6>] warn_slowpath_common+0x86/0xc0
>   [<ffffffff8106bdaa>] warn_slowpath_null+0x1a/0x20
>   [<ffffffffa05511ee>] ieee80211_get_tx_rates+0x22e/0x620 [mac80211]
>   [<ffffffffa0782232>] ? rtl_is_special_data+0x32/0x240 [rtlwifi]
>   [<ffffffffa055209e>] ? rate_control_get_rate+0xce/0x150 [mac80211]
>   [<ffffffff810bfc7d>] ? trace_hardirqs_on+0xd/0x10
>   [<ffffffff81071cc5>] ? __local_bh_enable_ip+0x65/0xd0
> --- traceback terminated here ---
>
> The problem is that IEEE80211_TX_RC_VHT_MCS is not set in the rate flags.
>
> Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
> Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
> Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
> Cc: Stable <stable@vger.kernel.org>

Isn't the commit log somewhat misleading as VHT was completely _broken_?
Do you mind if I change the commit log to this:

----------------------------------------------------------------------
rtlwifi: fix broken VHT support

When using a 5G-capable device with VHT (802.11ac) rates enabled was not
working (packets were not delivered) and the following mac80211 warning
was printed:

...
----------------------------------------------------------------------

-- 
Kalle Valo