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    SubjectRe: [PATCH] drivers: video: Remove useless checks
    On 05/26/2011 03:30 AM, Maxin B John wrote:
    > Hi,
    >
    > On Wed, May 25, 2011 at 1:47 PM, Tim Gardner<tim.gardner@canonical.com> wrote:
    >> On 05/19/2011 12:27 PM, Maxin B John wrote:
    >>>
    >>> Comparing unsigned less than zero will never be true.
    >>> Removing similar checks from 'fbmem.c' and 'fbcmap.c'.
    >>
    >> Looks right to me, though there are other places that suffer from the same
    >> issue. See fb_set_cmap() and its use of 'int start' and cmap->start.
    >
    > Thank you very much for reviewing the patch. As per your suggestion, I
    > have checked
    > the scenario is fb_set_cmap() and the use of 'int start' and 'cmap->start'.
    >
    > IMHO, that scenario doesn't fall under the comparison of unsigned int
    > < 0. That scenario
    > looks similar to the below given code to me:
    > /*---------------------------------*/
    > #include<stdio.h>
    >
    > int
    > main ()
    > {
    > unsigned int u_int = -1;
    > int s_int = 0;
    > s_int = u_int;
    > if (s_int< 0)
    > printf ("s_int is less than 0\n");
    > return 0;
    > }
    > /*---------------------------------*/
    >
    > Please let me know your comments.
    >
    > Best Regards,
    > Maxin
    >

    IMHO mixing signed and unsigned comparisons like this is just wrong. Its
    unnecessarily complicated and misleading, especially for a device
    driver. I'm a firm believer in the KISS philosophy for driver development.

    Its likely that the reason the fb code got into this situation is
    because a type was changed from signed to unsigned whence long ago, and
    nobody has bothered to clean it up.

    rtg
    --
    Tim Gardner tim.gardner@canonical.com


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