git: 2acbe67787d2 - main - sound(4): fixing panic for INVARIANTS kernel

[Tai-hwa Liang]

The branch main has been updated by avatar:

URL: https://cgit.FreeBSD.org/src/commit/?id=2acbe67787d2ba08b62713ccc3abcef01e7ced09

commit 2acbe67787d2ba08b62713ccc3abcef01e7ced09
Author:     Tai-hwa Liang <avatar at FreeBSD.org>
AuthorDate: 2021-04-22 12:45:18 +0000
Commit:     Tai-hwa Liang <avatar at FreeBSD.org>
CommitDate: 2021-04-24 03:27:43 +0000

    sound(4): fixing panic for INVARIANTS kernel
    
    3e7bae08210e0 turns the BUS_READ_IVAR() failure from a warning into a
    KASSERT.  For certain PCI audio devices such like snd_csa(4) and
    snd_emu10kx(4), the ac97_create() keeps the device handler generated
    by device_add_child(pci_dev, "pcm"), which is not really a PCI device
    handler.  This in turn causes the subsequent pci_get_subdevice()
    inside ac97_initmixer() triggering a panic.
    
    This patch tries to put a bandaid for the aforementioned pcm device
    children such that they can use the correct PCI handler(from parent)
    to avoid a KASSERT panic in the INVARIANTS kernel.
    
    Tested with:    snd_csa(4), snd_ich(4), snd_emu10kx(4)
    Reviewed by:    imp
    MFC after:      1 month
---
 sys/dev/sound/pcm/ac97.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/sys/dev/sound/pcm/ac97.c b/sys/dev/sound/pcm/ac97.c
index 960176329b3e..3dc614083660 100644
--- a/sys/dev/sound/pcm/ac97.c
+++ b/sys/dev/sound/pcm/ac97.c
@@ -602,6 +602,7 @@ ac97_initmixer(struct ac97_info *codec)
 	ac97_patch codec_patch;
 	const char *cname, *vname;
 	char desc[80];
+	device_t pdev;
 	u_int8_t model, step;
 	unsigned i, j, k, bit, old;
 	u_int32_t id;
@@ -641,9 +642,14 @@ ac97_initmixer(struct ac97_info *codec)
 		return ENODEV;
 	}
 
+	pdev = codec->dev;
+	while (strcmp(device_get_name(device_get_parent(pdev)), "pci") != 0) {
+		/* find the top-level PCI device handler */
+		pdev = device_get_parent(pdev);
+	}
 	codec->id = id;
-	codec->subvendor = (u_int32_t)pci_get_subdevice(codec->dev) << 16;
-	codec->subvendor |= (u_int32_t)pci_get_subvendor(codec->dev) &
+	codec->subvendor = (u_int32_t)pci_get_subdevice(pdev) << 16;
+	codec->subvendor |= (u_int32_t)pci_get_subvendor(pdev) &
 	    0x0000ffff;
 	codec->noext = 0;
 	codec_patch = NULL;