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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Giacomo Guiduzzi <guiduzzi.giacomo@gmail.com>,
	Paolo Valente <paolo.valente@linaro.org>,
	Takashi Iwai <tiwai@suse.de>
Subject: [PATCH 5.17 18/39] ALSA: pci: fix reading of swapped values from pcmreg in AC97 codec
Date: Fri, 25 Mar 2022 16:14:33 +0100	[thread overview]
Message-ID: <20220325150420.764837965@linuxfoundation.org> (raw)
In-Reply-To: <20220325150420.245733653@linuxfoundation.org>

From: Giacomo Guiduzzi <guiduzzi.giacomo@gmail.com>

commit 17aaf0193392cb3451bf0ac75ba396ec4cbded6e upstream.

Tests 72 and 78 for ALSA in kselftest fail due to reading
inconsistent values from some devices on a VirtualBox
Virtual Machine using the snd_intel8x0 driver for the AC'97
Audio Controller device.
Taking for example test number 72, this is what the test reports:
"Surround Playback Volume.0 expected 1 but read 0, is_volatile 0"
"Surround Playback Volume.1 expected 0 but read 1, is_volatile 0"
These errors repeat for each value from 0 to 31.

Taking a look at these error messages it is possible to notice
that the written values are read back swapped.
When the write is performed, these values are initially stored in
an array used to sanity-check them and write them in the pcmreg
array. To write them, the two one-byte values are packed together
in a two-byte variable through bitwise operations: the first
value is shifted left by one byte and the second value is stored in the
right byte through a bitwise OR. When reading the values back,
right shifts are performed to retrieve the previously stored
bytes. These shifts are executed in the wrong order, thus
reporting the values swapped as shown above.

This patch fixes this mistake by reversing the read
operations' order.

Signed-off-by: Giacomo Guiduzzi <guiduzzi.giacomo@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220322200653.15862-1-guiduzzi.giacomo@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 sound/pci/ac97/ac97_codec.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/sound/pci/ac97/ac97_codec.c
+++ b/sound/pci/ac97/ac97_codec.c
@@ -938,8 +938,8 @@ static int snd_ac97_ad18xx_pcm_get_volum
 	int codec = kcontrol->private_value & 3;
 	
 	mutex_lock(&ac97->page_mutex);
-	ucontrol->value.integer.value[0] = 31 - ((ac97->spec.ad18xx.pcmreg[codec] >> 0) & 31);
-	ucontrol->value.integer.value[1] = 31 - ((ac97->spec.ad18xx.pcmreg[codec] >> 8) & 31);
+	ucontrol->value.integer.value[0] = 31 - ((ac97->spec.ad18xx.pcmreg[codec] >> 8) & 31);
+	ucontrol->value.integer.value[1] = 31 - ((ac97->spec.ad18xx.pcmreg[codec] >> 0) & 31);
 	mutex_unlock(&ac97->page_mutex);
 	return 0;
 }



  parent reply	other threads:[~2022-03-25 15:26 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-25 15:14 [PATCH 5.17 00/39] 5.17.1-rc1 review Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 01/39] tpm: Fix error handling in async work Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 02/39] Bluetooth: btusb: Add another Realtek 8761BU Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 03/39] llc: fix netdevice reference leaks in llc_ui_bind() Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 04/39] ASoC: sti: Fix deadlock via snd_pcm_stop_xrun() call Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 05/39] ALSA: oss: Fix PCM OSS buffer allocation overflow Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 06/39] ALSA: usb-audio: add mapping for new Corsair Virtuoso SE Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 07/39] ALSA: hda/realtek: Add quirk for Clevo NP70PNJ Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 08/39] ALSA: hda/realtek: Add quirk for Clevo NP50PNJ Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 09/39] ALSA: hda/realtek - Fix headset mic problem for a HP machine with alc671 Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 10/39] ALSA: hda/realtek: Add quirk for ASUS GA402 Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 11/39] ALSA: pcm: Fix races among concurrent hw_params and hw_free calls Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 12/39] ALSA: pcm: Fix races among concurrent read/write and buffer changes Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 13/39] ALSA: pcm: Fix races among concurrent prepare and hw_params/hw_free calls Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 14/39] ALSA: pcm: Fix races among concurrent prealloc proc writes Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 15/39] ALSA: pcm: Add stream lock during PCM reset ioctl operations Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 16/39] ALSA: usb-audio: Add mute TLV for playback volumes on RODE NT-USB Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 17/39] ALSA: cmipci: Restore aux vol on suspend/resume Greg Kroah-Hartman
2022-03-25 15:14 ` Greg Kroah-Hartman [this message]
2022-03-25 15:14 ` [PATCH 5.17 19/39] drivers: net: xgene: Fix regression in CRC stripping Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 20/39] netfilter: nf_tables: initialize registers in nft_do_chain() Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 21/39] netfilter: nf_tables: validate registers coming from userspace Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 22/39] ACPI / x86: Work around broken XSDT on Advantech DAC-BJ01 board Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 23/39] ACPI: battery: Add device HID and quirk for Microsoft Surface Go 3 Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 24/39] ACPI: video: Force backlight native for Clevo NL5xRU and NL5xNU Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 25/39] crypto: qat - disable registration of algorithms Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 26/39] Bluetooth: btusb: Add one more Bluetooth part for the Realtek RTL8852AE Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 27/39] Bluetooth: hci_sync: Add a new quirk to skip HCI_FLT_CLEAR_ALL Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 28/39] Bluetooth: btusb: Use quirk to skip HCI_FLT_CLEAR_ALL on fake CSR controllers Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 29/39] Revert "ath: add support for special 0x0 regulatory domain" Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 30/39] drm/virtio: Ensure that objs is not NULL in virtio_gpu_array_put_free() Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 31/39] jbd2: fix use-after-free of transaction_t race Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 32/39] rcu: Dont deboost before reporting expedited quiescent state Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 33/39] uaccess: fix integer overflow on access_ok() Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 34/39] mac80211: fix potential double free on mesh join Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 35/39] tpm: fix reference counting for struct tpm_chip Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 36/39] tpm: use try_get_ops() in tpm-space.c Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 37/39] wcn36xx: Differentiate wcn3660 from wcn3620 Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 38/39] m68k: fix access_ok for coldfire Greg Kroah-Hartman
2022-03-25 15:14 ` [PATCH 5.17 39/39] nds32: fix access_ok() checks in get/put_user Greg Kroah-Hartman
2022-03-25 23:22 ` [PATCH 5.17 00/39] 5.17.1-rc1 review Shuah Khan
2022-03-26  1:22 ` Fox Chen
2022-03-26  2:53 ` Rudi Heitbaum
2022-03-26  3:07 ` Florian Fainelli
2022-03-26  4:54 ` Naresh Kamboju
2022-03-26  9:55   ` Greg Kroah-Hartman
2022-03-26 12:26     ` Naresh Kamboju
2022-03-26 12:19 ` Bagas Sanjaya
2022-03-27  0:13 ` Ron Economos
2022-03-27  0:52 ` Guenter Roeck
2022-03-27  1:37 ` Justin Forbes

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