LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Nicholas Mc Guire <der.herr@hofr.at>
To: Tormod Volden <lists.tormod@gmail.com>
Cc: Scot Doyle <lkml14@scotdoyle.com>,
	Nicholas Mc Guire <hofrat@osadl.org>,
	Thomas Winischhofer <thomas@winischhofer.net>,
	Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
	Tomi Valkeinen <tomi.valkeinen@ti.com>,
	linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] video: fbdev: sis: condition with no effect
Date: Fri, 6 Feb 2015 14:43:34 +0100	[thread overview]
Message-ID: <20150206134334.GA32696@opentech.at> (raw)
In-Reply-To: <CAArsGaaTfkYcmL2tbxdbv_Jjwuj6HLE3URxHpq4-ju8wK-Ga7w@mail.gmail.com>

On Thu, 05 Feb 2015, Tormod Volden wrote:

> On Thu, Feb 5, 2015 at 9:45 PM, Scot Doyle wrote:
> > On Wed, 4 Feb 2015, Nicholas Mc Guire wrote:
> >> The if and the else branch code are identical - so the condition has no
> >> effect on the effective code - this patch removes the condition and the
> >> duplicated code.
> >>
> >> Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
> >> ---
> >>
> >> This code has been in here since commit 544393fe584d ("sisfb update") so I guess it is
> >> safe to simply remove the duplicated code if nobody noticed for 10 years.
> >>
> >> Note that the code is not really CodingStyle compliant - the lines inserted were formatted
> >> to satisfy the coding style but I'm unsure if it is not better to leave it in the
> >> old format.
> >>
> >> Patch was only compile tested with x86_64_defconfig +
> >> CONFIG_FB_SIS=m, CONFIG_FB_SIS_300=y, CONFIG_FB_SIS_315=y
> >>
> >> Patch is against 3.19.0-rc7 (localversion-next is -next-20150204)
> >>
> >>  drivers/video/fbdev/sis/init301.c |    9 ++-------
> >>  1 file changed, 2 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/drivers/video/fbdev/sis/init301.c b/drivers/video/fbdev/sis/init301.c
> >> index 295e0de..9533a8ab 100644
> >> --- a/drivers/video/fbdev/sis/init301.c
> >> +++ b/drivers/video/fbdev/sis/init301.c
> >> @@ -7971,13 +7971,8 @@ SiS_SetCHTVReg(struct SiS_Private *SiS_Pr, unsigned short ModeNo, unsigned short
> >>           }
> >>        } else {                                               /* ---- PAL ---- */
> >>           /* We don't play around with FSCI in PAL mode */
> >> -         if(resindex == 0x04) {
> >> -            SiS_SetCH70xxANDOR(SiS_Pr,0x20,0x00,0xEF);       /* loop filter off */
> >> -            SiS_SetCH70xxANDOR(SiS_Pr,0x21,0x01,0xFE);       /* ACIV on */
> >> -         } else {
> >> -            SiS_SetCH70xxANDOR(SiS_Pr,0x20,0x00,0xEF);       /* loop filter off */
> >> -            SiS_SetCH70xxANDOR(SiS_Pr,0x21,0x01,0xFE);       /* ACIV on */
> >> -         }
> >> +       SiS_SetCH70xxANDOR(SiS_Pr, 0x20, 0x00, 0xEF); /* loop filter off */
> >> +       SiS_SetCH70xxANDOR(SiS_Pr, 0x21, 0x01, 0xFE); /* ACIV on */
> >>        }
> >>
> >>  #endif  /* 300 */
> >
> > The code covering the PAL case had this redundancy when it was introduced
> > in Linux 2.4.19.
> >
> > Lines 7934-7981 consider three variables: PAL, overscan, and resindex.
> > Given the "#ifdef 0" block, couldn't the current six sections collapse
> > into two? One for (!PAL && overscan && resindex==5) and another for the
> > rest?
> 
> Are we sure there isn't a typo in one of the duplicate clauses? Or
> wrong copy-pasting? Generally I am skeptical to "fixing" code without
> understanding what is behind or testing it, and just cosmetically
> brush over it. For now at least it is obvious that there is something
> wrong. In case (although an unlikely one) someone who understands the
> code and knows this chip comes along, he would quickly spot this.
> After your "fixups" this will be all forgotten. Additionally it adds
> to the impression that this code is being maintained, which is wrong.
> 
> I would understand an argument about annoying compiler warnings and
> the like, but in that case I would prefer to #if 0 it instead of
> "prettifying" it.
>
Its actually a static code checker that is fussing at this.
The #if 0 case is on my list as well - but thats a different 
scanner - and thus goes into a separate patch.

I agree that it could be a hidden bug - but given that its this
way for 10 years I doubt this.

thx!
hofrat

      parent reply	other threads:[~2015-02-06 13:43 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-04 11:36 Nicholas Mc Guire
2015-02-05 20:45 ` Scot Doyle
2015-02-05 21:27   ` Tormod Volden
2015-02-05 23:37     ` Scot Doyle
2015-02-06  7:00     ` Thomas Winischhofer
2015-02-06 13:47       ` Nicholas Mc Guire
2015-02-06 14:32         ` Thomas Winischhofer
2015-02-06 13:43     ` Nicholas Mc Guire [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20150206134334.GA32696@opentech.at \
    --to=der.herr@hofr.at \
    --cc=hofrat@osadl.org \
    --cc=linux-fbdev@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lists.tormod@gmail.com \
    --cc=lkml14@scotdoyle.com \
    --cc=plagnioj@jcrosoft.com \
    --cc=thomas@winischhofer.net \
    --cc=tomi.valkeinen@ti.com \
    --subject='Re: [PATCH RFC] video: fbdev: sis: condition with no effect' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).