Re: [PATCH] PCI: mediatek: Verify whether the free_ck clock is ungated or not
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2021-04-29 22:38:42
Also in:
linux-mediatek, linux-pci, lkml
Can you make the subject say something at a higher level instead of just paraphrasing the C code? I'm guessing this means resume will now fail if the clock isn't turned on? On Thu, Apr 29, 2021 at 07:17:49PM +0530, Amey Narkhede wrote:
Verify that the free_ck clock is ungated on device resume by checking return value of clk_prepare_enable().
Also the commit log -- this doesn't say anything more than the code itself. Did you find this by tripping over it? Or just by code inspection? I guess without the check, we continue on and try to resume, but accesses to PCI devices fail and maybe return ~0 data or cause machine checks or something?
quoted hunk ↗ jump to hunk
Signed-off-by: Amey Narkhede <redacted> --- drivers/pci/controller/pcie-mediatek.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c index 23548b517..9b13214bf 100644 --- a/drivers/pci/controller/pcie-mediatek.c +++ b/drivers/pci/controller/pcie-mediatek.c@@ -1154,11 +1154,14 @@ static int __maybe_unused mtk_pcie_resume_noirq(struct device *dev) { struct mtk_pcie *pcie = dev_get_drvdata(dev); struct mtk_pcie_port *port, *tmp; + int ret; if (list_empty(&pcie->ports)) return 0; - clk_prepare_enable(pcie->free_ck); + ret = clk_prepare_enable(pcie->free_ck); + if (ret) + return ret;
Most callers print an error message when clk_prepare_enable() fails.
list_for_each_entry_safe(port, tmp, &pcie->ports, list) mtk_pcie_enable_port(port); -- 2.31.1
_______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel