Re: [PATCH v4 1/5] fsl-diu-fb: fix issue with re-enabling DIU area descriptor

On Wed, 28 Jul 2010 01:02:59 -0600
Grant Likely [off-list ref] wrote:
...

quoted

=C2=A0drivers/video/fsl-diu-fb.c | =C2=A0 38 +++++++++++++++++++++++---=

------------

quoted

=C2=A01 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
index 27455ce..9b8c991 100644
--- a/drivers/video/fsl-diu-fb.c
+++ b/drivers/video/fsl-diu-fb.c

@@ -317,6 +317,17 @@ static void fsl_diu_free(void *virt, size_t size)

=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0free_pages_exact=

(virt, size);

quoted

=C2=A0}

+/*
+ * Workaround for failed writing desc register of planes.
+ * Needed with MPC5121 DIU rev 2.0 silicon.
+ */
+void wr_reg_wa(u32 *reg, u32 val)
+{
+ =C2=A0 =C2=A0 =C2=A0 do {
+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 out_be32(reg, val);
+ =C2=A0 =C2=A0 =C2=A0 } while (in_be32(reg) !=3D val);
+}

=20
I'll apply this one, but it looks like a potential problem.  What
happens if the write never succeeds?  The kernel then gets stuck in a
forever busy loop.  You should look at reworking it.

I'll submit an incremental patch that prevents looping forever in
the case if the write never succeeds. Thanks!

Anatolij