[PATCH] usb: xhci: Fix HCS_ERST_MAX conversion
Chen-Yu Tsai <[email protected]>
| Newsgroups | org.kernel.vger.linux-usb,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
This partially reverts commit 6d45e9556d4a11b726e897d86e095b96db4550d8.
HCS_ERST_MAX holds power of 2 value for maximum number of segments.
In the culprit commit, this was incorrectly converted to "shift up 2".
On hardware where this field is zero, this results in xhci_alloc_erst()
calling dma_alloc_coherent() with size = 0, leading to a horrible splat
and non-usable XHCI.
Revert the shift-up-2 to the BIT() macro.
Fixes: 6d45e9556d4a ("usb: xhci: standardize multi bit-field macros")
Cc: Niklas Neronin <[email protected]>
Signed-off-by: Chen-Yu Tsai <[email protected]>
---
This immediately fixes XHCI for me. This was observed on next-20260818
and next-20260819.
---
drivers/usb/host/xhci-mem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 7a21ac81f9c8..af8d4b74c4ba 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2301,7 +2301,7 @@ xhci_alloc_interrupter(struct xhci_hcd *xhci, unsigned int segs, gfp_t flags)
if (!segs)
segs = ERST_DEFAULT_SEGS;
- max_segs = FIELD_GET(HCS_ERST_MAX, xhci->hcs_params2) << 2;
+ max_segs = BIT(FIELD_GET(HCS_ERST_MAX, xhci->hcs_params2));
segs = min(segs, max_segs);
ir = kzalloc_node(sizeof(*ir), flags, dev_to_node(dev));
--
2.55.0.860.g4b6b3295ed-goog