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andy-shev / linux

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hsu_dma_pci: disable spurious interrupt #28

Closed htot closed 3 years ago

htot commented 3 years ago

On Intel Tangier B0 and Anniedale the interrupt line, disregarding to have different numbers, is shared between HSU DMA and UART IPs. Thus on such SoCs we are expecting that IRQ handler is called in UART driver only. hsu_pci_irq was handling the spurious interrupt from HSU DMA by returning immediately. This wastes CPU time and since HSU DMA and HSU UART interrupt occur simultaneously they race to be handled causing delay to the HSU UART interrupt handling. Fix this by disabling the interrupt entirely.

Fixes: 4831e0d9054c ("serial: 8250_mid: handle interrupt correctly in DMA case") Signed-off-by: Ferry Toth ftoth@exalondelft.nl

andy-shev commented 3 years ago

And title for the commit has to be dmaengine: hsu: ...

htot commented 3 years ago

6043c32 should be OK now

andy-shev commented 3 years ago

@htot the title prefix seems not addressed.

htot commented 3 years ago

Hi @andy-shev yes, sorry I only saw your comment on the title after sending to patch to lkml. I guess I will need to fix the title in v2.

htot commented 3 years ago

As it is now in upstream I close this one.