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From: Arnd Bergmann <arnd@arndb.de>
To: Takashi Iwai <tiwai@suse.com>,
	Connor McAdams <conmanx360@gmail.com>,
	Takashi Sakamoto <o-takashi@sakamocchi.jp>
Cc: clang-built-linux@googlegroups.com,
	Nick Desaulniers <ndesaulniers@google.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>, Jaroslav Kysela <perex@perex.cz>,
	Alastair Bridgewater <alastair.bridgewater@gmail.com>,
	alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org
Subject: [PATCH] ALSA: hda/ca0132: work around clang -Wuninitialized warning
Date: Fri, 22 Mar 2019 15:06:28 +0100	[thread overview]
Message-ID: <20190322140649.197027-1-arnd@arndb.de> (raw)

When CONFIG_PCI is disabled, clang gets confused about the
control flow of the switch() statement always ending up
in the default case, and warns:

sound/pci/hda/patch_ca0132.c:7558:6: error: variable 'fw_entry' is used uninitialized whenever 'if' condition is false
      [-Werror,-Wsometimes-uninitialized]
        if (!spec->alt_firmware_present) {
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~
sound/pci/hda/patch_ca0132.c:7565:42: note: uninitialized use occurs here
        dsp_os_image = (struct dsp_image_seg *)(fw_entry->data);
                                                ^~~~~~~~
sound/pci/hda/patch_ca0132.c:7558:2: note: remove the 'if' if its condition is always true
        if (!spec->alt_firmware_present) {
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sound/pci/hda/patch_ca0132.c:7521:33: note: initialize the variable 'fw_entry' to silence this warning
        const struct firmware *fw_entry;
                                       ^
                                        = NULL

Adding an explicit check for CONFIG_PCI avoids the issue.
Unfortunately this is not very intuitive here.

Link: https://bugs.llvm.org/show_bug.cgi?id=41197#c1
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
Any suggestions for other workarounds appreciated. If you can think
of a better fix, please treat this as a reported-by:
---
 sound/pci/hda/patch_ca0132.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/pci/hda/patch_ca0132.c b/sound/pci/hda/patch_ca0132.c
index 29882bda7632..415b16b7db70 100644
--- a/sound/pci/hda/patch_ca0132.c
+++ b/sound/pci/hda/patch_ca0132.c
@@ -7555,7 +7555,7 @@ static bool ca0132_download_dsp_images(struct hda_codec *codec)
 	 * Use default ctefx.bin if no alt firmware is detected, or if none
 	 * exists for your particular codec.
 	 */
-	if (!spec->alt_firmware_present) {
+	if (!IS_ENABLED(CONFIG_PCI) || !spec->alt_firmware_present) {
 		codec_dbg(codec, "Default firmware selected.");
 		if (request_firmware(&fw_entry, EFX_FILE,
 					codec->card->dev) != 0)
-- 
2.20.0


             reply	other threads:[~2019-03-22 14:08 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-22 14:06 Arnd Bergmann [this message]
2019-03-22 14:53 ` [PATCH] ALSA: hda/ca0132: work around clang -Wuninitialized warning Nathan Chancellor
2019-03-22 15:00 ` Takashi Iwai
2019-03-22 15:00   ` Takashi Iwai
2019-03-22 15:12   ` Arnd Bergmann
2019-03-22 15:13   ` Nathan Chancellor

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