Messages in this thread | | | From | Andy Shevchenko <> | Date | Wed, 26 Jul 2017 13:44:32 +0300 | Subject | Re: [PATCH] ACPI, APEI: Fixup incorrect 16-bit access width firmware bug |
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On Wed, Jul 26, 2017 at 9:16 AM, Liwei Song <liwei.song@windriver.com> wrote: > On 07/21/2017 05:56 PM, Andy Shevchenko wrote: >> On Fri, Jul 21, 2017 at 12:41 PM, Song liwei <liwei.song@windriver.com> wrote:
>> /* Fixup common BIOS bug */ >> if (bit_offset == 0) { >> if (bit_width == 16 && (*paddr & 0x01) == 0 && *access_bit_width < 16) >> *access_bit_width = 16; >> else if (bit_width == 32 && (*paddr & 0x03) == 0 && >> *access_bit_width < 32) >> *access_bit_width = 32; >> else if (bit_width == 64 && (*paddr & 0x07) == 0 && >> *access_bit_width < 64) >> *access_bit_width = 64; >> }
> Thanks for your suggestion, what about the condition like the following? > The main bug in bios is bit_width is not comfortable with access_bit_width > So check it first. > > if (*access_bit_width < bit_width && bit_offset == 0) { > if ((bit_width == 16 && (*paddr & 0x01) == 0) || > (bit_width == 32 && (*paddr & 0x03) == 0) || > (bit_width == 64 && (*paddr & 0x07) == 0)) > *access_bit_width = bit_width; > }
Either works to me.
P.S. Less explicit case is to use bit operations to check those, i.e. is_power_of_2(), fls().
-- With Best Regards, Andy Shevchenko
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