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SubjectRe: [PATCH v2 2/2] arm/tegra: add timeout to PCIe PLL lock detection loop
On 03/09/2012 03:09 AM, Dmitry Artamonow wrote:
> Tegra PCIe driver waits for PLL to lock using busy loop.
> If PLL fails to lock for some reason, this leads to silent lockup
> while booting (PCIe code is not modular).
>
> Fix by adding timeout, so if PLL doesn't lock in a couple
> of seconds, just PCIe driver fails and machine continues to boot.
>
> Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>

> diff --git a/arch/arm/mach-tegra/pcie.c b/arch/arm/mach-tegra/pcie.c

> /* Wait for the PLL to lock */
> + timeout = 2000;
> do {
> val = pads_readl(PADS_PLL_CTL);
> + usleep_range(1000, 1000);
> + if (--timeout == 0) {
> + pr_err("Tegra PCIe error: timeout waiting for PLL\n");
> + return -EBUSY;
> + }
> } while (!(val & PADS_PLL_CTL_LOCKDET));

Thierry pointed out that one of NVIDIA's downstream kernels uses a
timeout of 300 here, rather than 2000 above. Do you see a specific need
for this timeout for be 2000 rather than 300? It might be nice to be
consistent.

Olof, I notice you've already applied V1 of this, which has the return
statement issue. Can you replace it with this, or should Dmitry send an
incremental patch?


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