Ping again -- any one has further comment for the v3 version? It looks the framebuffer layer's Tomi and Jean-Christophe are out recently? Recently I don't see mail from them since Jul 1 and Jul 8 in the lists. Though the patch belongs to driver/video/fbdev/, it only changes hyper-v stuff and only changes one file and the patch itself is straightforward IMO. So, hi Greg and all, If you think the patch itself is OK, may I know if it's OK for the patch to go into Greg's char-misc.git tree, as some other hyper-v patches did? Please let me know what's the next step I should do. I appreciate your reply. Thanks! -- Dexuan > -----Original Message----- > From: linux-kernel-owner@xxxxxxxxxxxxxxx [mailto:linux-kernel- > owner@xxxxxxxxxxxxxxx] On Behalf Of Dexuan Cui > Sent: Wednesday, July 9, 2014 11:04 AM > To: gregkh@xxxxxxxxxxxxxxxxxxx; dan.carpenter@xxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx; > plagnioj@xxxxxxxxxxxx; tomi.valkeinen@xxxxxx; linux-fbdev@xxxxxxxxxxxxxxx > Cc: olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx; jasowang@xxxxxxxxxx; KY > Srinivasan; Haiyang Zhang > Subject: [PATCH v3] video: hyperv: hyperv_fb: refresh the VM screen by force > on VM panic > > Currently the VSC has no chance to notify the VSP of the dirty rectangle on > VM > panic because the notification work is done in a workqueue, and in panic() > the > kernel typically ends up in an infinite loop, and a typical kernel config has > CONFIG_PREEMPT_VOLUNTARY=y and CONFIG_PREEMPT is not set, so a > context switch > can't happen in panic() and the workqueue won't have a chance to run. As a > result, the VM Connection window can't refresh until it's closed and we > re-connect to the VM. > > We can register a handler on panic_notifier_list: the handler can notify > the VSC and switch the framebuffer driver to a "synchronous mode", > meaning > the VSC flushes any future framebuffer change to the VSP immediately. > > v2: removed the MS-TFS line in the commit message > v3: remove some 'unlikely' markings > > Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx> > Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > --- > drivers/video/fbdev/hyperv_fb.c | 58 > ++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 55 insertions(+), 3 deletions(-) > > diff --git a/drivers/video/fbdev/hyperv_fb.c > b/drivers/video/fbdev/hyperv_fb.c > index e23392e..a7b98e1 100644 > --- a/drivers/video/fbdev/hyperv_fb.c > +++ b/drivers/video/fbdev/hyperv_fb.c > @@ -226,11 +226,16 @@ struct hvfb_par { > u8 recv_buf[MAX_VMBUS_PKT_SIZE]; > }; > > +static struct fb_info *hvfb_info; > + > static uint screen_width = HVFB_WIDTH; > static uint screen_height = HVFB_HEIGHT; > static uint screen_depth; > static uint screen_fb_size; > > +/* If true, the VSC notifies the VSP on every framebuffer change */ > +static bool synchronous_fb; > + > /* Send message to Hyper-V host */ > static inline int synthvid_send(struct hv_device *hdev, > struct synthvid_msg *msg) > @@ -532,6 +537,20 @@ static void hvfb_update_work(struct work_struct *w) > schedule_delayed_work(&par->dwork, > HVFB_UPDATE_DELAY); > } > > +static int hvfb_on_panic(struct notifier_block *nb, > + unsigned long e, void *p) > +{ > + if (hvfb_info) > + synthvid_update(hvfb_info); > + > + synchronous_fb = true; > + > + return NOTIFY_DONE; > +} > + > +static struct notifier_block hvfb_panic_nb = { > + .notifier_call = hvfb_on_panic, > +}; > > /* Framebuffer operation handlers */ > > @@ -582,14 +601,41 @@ static int hvfb_blank(int blank, struct fb_info *info) > return 1; /* get fb_blank to set the colormap to all black */ > } > > +static void hvfb_cfb_fillrect(struct fb_info *p, > + const struct fb_fillrect *rect) > +{ > + cfb_fillrect(p, rect); > + > + if (synchronous_fb) > + synthvid_update(p); > +} > + > +static void hvfb_cfb_copyarea(struct fb_info *p, > + const struct fb_copyarea *area) > +{ > + cfb_copyarea(p, area); > + > + if (synchronous_fb) > + synthvid_update(p); > +} > + > +static void hvfb_cfb_imageblit(struct fb_info *p, > + const struct fb_image *image) > +{ > + cfb_imageblit(p, image); > + > + if (synchronous_fb) > + synthvid_update(p); > +} > + > static struct fb_ops hvfb_ops = { > .owner = THIS_MODULE, > .fb_check_var = hvfb_check_var, > .fb_set_par = hvfb_set_par, > .fb_setcolreg = hvfb_setcolreg, > - .fb_fillrect = cfb_fillrect, > - .fb_copyarea = cfb_copyarea, > - .fb_imageblit = cfb_imageblit, > + .fb_fillrect = hvfb_cfb_fillrect, > + .fb_copyarea = hvfb_cfb_copyarea, > + .fb_imageblit = hvfb_cfb_imageblit, > .fb_blank = hvfb_blank, > }; > > @@ -801,6 +847,9 @@ static int hvfb_probe(struct hv_device *hdev, > > par->fb_ready = true; > > + hvfb_info = info; > + atomic_notifier_chain_register(&panic_notifier_list, > &hvfb_panic_nb); > + > return 0; > > error: > @@ -820,6 +869,9 @@ static int hvfb_remove(struct hv_device *hdev) > struct fb_info *info = hv_get_drvdata(hdev); > struct hvfb_par *par = info->par; > > + atomic_notifier_chain_unregister(&panic_notifier_list, > &hvfb_panic_nb); > + hvfb_info = NULL; > + > par->update = false; > par->fb_ready = false; > > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
