* [PATCH] video: fbdev: aty: aty128fb: Replace mdelay with msleep in aty128_set_suspend
@ 2018-04-10 1:40 ` Jia-Ju Bai
2018-04-24 15:48 ` Bartlomiej Zolnierkiewicz
0 siblings, 1 reply; 2+ messages in thread
From: Jia-Ju Bai @ 2018-04-10 1:40 UTC (permalink / raw)
To: paulus, b.zolnierkie; +Cc: linux-fbdev, linux-kernel, Jia-Ju Bai
aty128_set_suspend() is never called in atomic context.
The call chains ending up at aty128_set_suspend() are:
[1] aty128_set_suspend() <- aty128_pci_suspend()
[2] aty128_set_suspend() <- aty128_do_resume() <- aty128_pci_resume()
[3] aty128_set_suspend() <- aty128_do_resume() <- aty128_early_resume()
aty128_pci_suspend() is set as ".suspend" in struct pci_driver.
aty128_pci_resume() is set as ".resume" in struct pci_driver.
aty128_early_resume() is never called.
These functions are not called in atomic context.
Despite never getting called from atomic context, aty128_set_suspend()
calls mdelay() to busily wait.
This is not necessary and can be replaced with msleep() to
avoid busy waiting.
This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
drivers/video/fbdev/aty/aty128fb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/fbdev/aty/aty128fb.c b/drivers/video/fbdev/aty/aty128fb.c
index db18474..15dfdff 100644
--- a/drivers/video/fbdev/aty/aty128fb.c
+++ b/drivers/video/fbdev/aty/aty128fb.c
@@ -2442,7 +2442,7 @@ static void aty128_set_suspend(struct aty128fb_par *par, int suspend)
(void)aty_ld_pll(POWER_MANAGEMENT);
aty_st_le32(BUS_CNTL1, 0x00000010);
aty_st_le32(MEM_POWER_MISC, 0x0c830000);
- mdelay(100);
+ msleep(100);
/* Switch PCI power management to D2 */
pci_set_power_state(pdev, PCI_D2);
--
1.9.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] video: fbdev: aty: aty128fb: Replace mdelay with msleep in aty128_set_suspend
2018-04-10 1:40 ` [PATCH] video: fbdev: aty: aty128fb: Replace mdelay with msleep in aty128_set_suspend Jia-Ju Bai
@ 2018-04-24 15:48 ` Bartlomiej Zolnierkiewicz
0 siblings, 0 replies; 2+ messages in thread
From: Bartlomiej Zolnierkiewicz @ 2018-04-24 15:48 UTC (permalink / raw)
To: Jia-Ju Bai; +Cc: paulus, linux-fbdev, linux-kernel
On Tuesday, April 10, 2018 09:40:35 AM Jia-Ju Bai wrote:
> aty128_set_suspend() is never called in atomic context.
>
> The call chains ending up at aty128_set_suspend() are:
> [1] aty128_set_suspend() <- aty128_pci_suspend()
> [2] aty128_set_suspend() <- aty128_do_resume() <- aty128_pci_resume()
> [3] aty128_set_suspend() <- aty128_do_resume() <- aty128_early_resume()
>
> aty128_pci_suspend() is set as ".suspend" in struct pci_driver.
> aty128_pci_resume() is set as ".resume" in struct pci_driver.
> aty128_early_resume() is never called.
> These functions are not called in atomic context.
>
> Despite never getting called from atomic context, aty128_set_suspend()
> calls mdelay() to busily wait.
> This is not necessary and can be replaced with msleep() to
> avoid busy waiting.
>
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
>
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Patch queued for 4.18, thanks.
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
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2018-04-10 1:40 ` [PATCH] video: fbdev: aty: aty128fb: Replace mdelay with msleep in aty128_set_suspend Jia-Ju Bai
2018-04-24 15:48 ` Bartlomiej Zolnierkiewicz
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