From mboxrd@z Thu Jan 1 00:00:00 1970 From: balbi@ti.com (Felipe Balbi) Date: Wed, 15 Oct 2014 09:41:40 -0500 Subject: [PATCH 1/3] video: fbdev: omap2: omapfb: remove __exit annotation In-Reply-To: <543E64EE.4070104@ti.com> References: <1413311335-25083-1-git-send-email-balbi@ti.com> <543E64EE.4070104@ti.com> Message-ID: <20141015144140.GD10888@saruman> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On Wed, Oct 15, 2014 at 03:13:34PM +0300, Tomi Valkeinen wrote: > Hi, > > On 14/10/14 21:28, Felipe Balbi wrote: > > if we leave __exit annotation, driver can't be unbound > > through sysfs. > > > > Signed-off-by: Felipe Balbi > > --- > > drivers/video/fbdev/omap2/omapfb/omapfb-main.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/video/fbdev/omap2/omapfb/omapfb-main.c b/drivers/video/fbdev/omap2/omapfb/omapfb-main.c > > index ec2d132..9cbf1ce 100644 > > --- a/drivers/video/fbdev/omap2/omapfb/omapfb-main.c > > +++ b/drivers/video/fbdev/omap2/omapfb/omapfb-main.c > > @@ -2619,7 +2619,7 @@ err0: > > return r; > > } > > > > -static int __exit omapfb_remove(struct platform_device *pdev) > > +static int omapfb_remove(struct platform_device *pdev) > > { > > struct omapfb2_device *fbdev = platform_get_drvdata(pdev); > > > > @@ -2636,7 +2636,7 @@ static int __exit omapfb_remove(struct platform_device *pdev) > > > > static struct platform_driver omapfb_driver = { > > .probe = omapfb_probe, > > - .remove = __exit_p(omapfb_remove), > > + .remove = omapfb_remove, > > .driver = { > > .name = "omapfb", > > .owner = THIS_MODULE, > > Interesting. I don't know if I'm doing something funny, but without this > patch, I can unbind omapfb, kind of. > > "echo omapfb > unbind" goes ok, but remove is obviously not called. remove isn't called because it won't exist if it's built-in. Look at the definition of __exit_p() > Somehow omapfb device is still unbound from the driver, as I can then > bind it again, causing probe to be called. Which breaks everything. > > I would've thought that unbinding is not possible if remove is missing, > but that doesn't seem to be the case. I guess it just means that remove > is not called when the driver & device are unbound. if no remove it provided on platform_driver structure, platform bus assumes you have nothing to do on your ->remove(), so you end up leaking all resources you allocated on ->probe() (unless you *really* don't need to do anything on ->remove). > We have 18 __exit_p()s in omapdss and related drivers. I guess they are > all broken the same way. yup, I should've grepped. > Note that omapfb unbind & bind does not work even with this patch, but > results in a crash as some old state is left into omapdss. The same > happens also with unloading and loading omapfb module (but keeping > omapdss module loaded). It worked fine for me. I unbound and bound omapfb multiple times. > So there seems to be more issues around this. quite a few more, I'd say -- balbi -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: