[Pw_forum] eigenvalues not converged in ph.x

[lfhuang at theory.issp.ac.cn]

Dear all pwscf friends:
  Although there are so much messages on "WARNING: # eigenvalues not
converged" in pw.x, this problem in ph.x is not frequently talked.
This time, I calculate the phonon dispersions in graphene. The
convergence can be easily obtained in pw.x without any warnings, but
when ph.x is executed, there always appear hundreds warning lines:

     G cutoff =  215.4158  (  47155 G-vectors)     FFT grid: ( 30, 30,125)
     G cutoff =   86.1663  (  11933 G-vectors)  smooth grid: ( 20, 20, 80)

     nbndx  =    32  nbnd   =     8  natomwfc =     8  npwx   =     152
     nelec  =   8.00  nkb   =    16  ngl    =    1449

     The potential is recalculated from file :
     graphene.save/charge-density.xml


     negative rho (up, down):  0.326E-05 0.000E+00
     Starting wfc are atomic

     total cpu time spent up to now is    387.33 secs

     Band Structure Calculation
     Davidson diagonalization with overlap
     WARNING:     2 eigenvalues not converged
     WARNING:     1 eigenvalues not converged
     ...................
     (nearly 900 lines!!!)
     ...................
     WARNING:     2 eigenvalues not converged
     WARNING:     1 eigenvalues not converged
     ethr =  1.25E-10,  avg # of iterations = 23.1

     total cpu time spent up to now is    732.55 secs

     End of band structure calculation


I have taken so much pain testing according to the userguide and some
message on the mailing list(maybe those discriptions are not exactly
suitable for ph.x). Or maybe there is something important/subtle I
have missed.
Thanks a lot for reading my letter!
Appreciate greatly the one who can help me!!