linux-kernel - Re: GMA500: ERROR: "__bad

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4E2CC6CC.5020204@gmail.com>
Date:	Mon, 25 Jul 2011 11:28:44 +1000
From:	Ryan Mallon <rmallon@...il.com>
To:	Jesper Juhl <jj@...osbits.net>
CC:	linux-kernel@...r.kernel.org, Alan Cox <alan@...ux.intel.com>,
	Greg Kroah-Hartman <gregkh@...e.de>, devel@...verdev.osuosl.org
Subject: Re: GMA500: ERROR: "__bad_udelay" undefined!

On 25/07/11 11:22, Ryan Mallon wrote:
> On 25/07/11 07:37, Jesper Juhl wrote:
>> Just got this when building the attached .config on x86_64 with gcc 
>> 4.6.1
>> on up-to-date mainline git tree (head at
>> b6844e8f64920cdee620157252169ba63afb0c89) :
>>
>>   ERROR: "__bad_udelay" [drivers/staging/gma500/psb_gfx.ko] undefined!
>>   make[1]: *** [__modpost] Error 1
>>
>> I don't need gma500, so I've just disabled the driver to get around 
>> it but
>> I thought some people might still like to know :)
>>
> __bad_udelay is a compile time check that constant udelays do not 
> exceed a certain threshold. For x86_64 it used to be n > 20000, now it 
> is n / 20000 >= 1. The problem is in 
> drivers/staging/gma500/psb_intel_display.c:psb_init_wait_for_vblank, 
> which does udelay(20000) which under the old code would have been 
> fine, but fails the new __bad_udelay check.
>
> Possibly the udelay can just be converted to an mdelay?

Here is the patch:
----
A change to the constraints for the compile time check for __bad_udelay 
on some architectures caused breakage in the gma500 staging driver. Fix 
by replacing udelay with mdelay.

Signed-off-by: Ryan Mallon <rmallon@...il.com>
---

diff --git a/drivers/staging/gma500/psb_intel_display.c b/drivers/staging/gma500/psb_intel_display.c
index 4f47d09..09e378d 100644
--- a/drivers/staging/gma500/psb_intel_display.c
+++ b/drivers/staging/gma500/psb_intel_display.c
@@ -331,7 +331,7 @@ static bool psb_intel_find_best_PLL(struct drm_crtc *crtc, int target,
  void psb_intel_wait_for_vblank(struct drm_device *dev)
  {
  	/* Wait for 20ms, i.e. one cycle at 50hz. */
-	udelay(20000);
+	mdelay(20);
  }

  int psb_intel_pipe_set_base(struct drm_crtc *crtc,






--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/